Visualizing ConceptsThese exercises are intended

Problem 15PE Give the chemical formulas for (a) silicon tetrabromide, (b) disulfur dichloride.

Problem 16E The Atomic Theory of Matter and the Discovery of Atomic Structure (Sections) Millikan determined the charge on the electron by studying the static charges on oil drops falling in an electric field (Figure). A student carried out this experiment using several oil drops for her measurements and calculated the charges on the drops. She obtained the following data: Droplet Calculated Charge (C) A 1.60 × 10-19 B 3.15 × 10-19 C 4.81 × 10-19 D 6.31 × 10-19 Figure Would the masses of the oil drops be changed significantly by any electrons that accumulate on them? Figure Millikan’s oil-drop experiment to measure the charge of the electron. Small drops of oil are allowed to fall between electrically charged plates. The drops pick up extra electrons as a result of irradiation by X-rays and so became negatively charged. Millikan measured how varying the voltage between the plates affected the rate of fall. From these data he calculated the negative charge on the drops. Because the charge on any drop was always some integral multiple of 1.602 × 10-19 C, Millikan deduced this value to be the charge of a single electron. (a) What is the significance of the fact that the droplets carried different charges? ________________ (b) What conclusion can the student draw from these data regarding the charge of the electron? ________________ (c) What value (and to how many significant figures) should she report for the electronic charge?

Problem 18E The Modern View of Atomic Structure; Atomic Weights (Sections) An atom of rhodium (Rh) has a diameter of about 2.7 × 10-8cm. (a) What is the radius of a rhodium atom in angstroms (Å) and in meters (m)? (b) How many Rh atoms would have to be placed side by side to span a distance of 6.0 mm? (c) If you assume that the Rh atom is a sphere, what is the volume in m3 of a single atom?

Problem 16PE (a) What is the molecular formula of butane, the alkane with four carbons? (b) What are the name and molecular formula of an alcohol derived from butane?

Problem 17E The Modern View of Atomic Structure; Atomic Weights (Sections) The radius of an atom of gold (Au) is about 1.35 Å. (a) Express this distance in nanometers (nm) and in picometers (pm) (b) How many gold atoms would have to be lined up to span 1.0 mm? (c) If the atom is assumed to be a sphere, what is the volume in cm3 of a single Au atom?

Problem 19E The Modern View of Atomic Structure; Atomic Weights (Sections) Answer the following questions without referring to Table: Table Comparison of the Proton, Neutron, and Electron Particle Charge Mass (amu) Proton Positive (1+) 1.0073 Neutron None (neutral) 1.0087 Electron Negative (1-) 5.486 × 10-4 (a) What are the main subatomic particles that make up the atom? (b) What is the relative charge (in multiples of the electronic charge) of each of the particles? (c) Which of the particles is the most massive? (d) Which is the least massive?

Problem 21E The Modern View of Atomic Structure; Atomic Weights (Sections) (a) Define atomic number and mass number. (b) Which of these can vary without changing the identity of the element?

Problem 20E The Modern View of Atomic Structure; Atomic Weights (Sections) Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (a) The nucleus has most of the mass and comprises most of the volume of an atom. (b) Every atom of a given element has the same number of protons. (c) The number of electrons in an atom equals the number of neutrons in the atom. (d) The protons in the nucleus of the helium atom are held together by a force called the strong nuclear force.

Problem 22E The Modern View of Atomic Structure; Atomic Weights (Sections) (a) Which two of the following are isotopes of the same element: 31 16X, 31 15X, 32 16X? (b) What is the identity of the element whose isotopes you have selected?

Fill in the gaps in the following table, assuming each column represents a neutral atom.

Problem 23E The Modern View of Atomic Structure; Atomic Weights (Sections) How many protons, neutrons, and electrons are in the following atoms? (a) 40Ar, (b) 65Zn, (c) 70Ga, (d) 80B, (e) 184W, (f) 243Am.

Fill in the gaps in the following table, assuming each column represents a neutral atom.

Problem 24E The Modern View of Atomic Structure; Atomic Weights (Sections) Each of the following isotopes is used in medicine. Indicate the number of protons and neutrons in each isotope: (a) phosphorus-32, (b) – chromium-51, (c) cobalt-60, (d) technetium-99, (e) iodine-131, (f) thallium-201.

Problem 30E The Modern View of Atomic Structure; Atomic Weights (Sections) (a) What is the mass in amu of a carbon-12 atom? (b) Why is the atomic weight of carbon reported as 12.011 in the table of elements and the periodic table in the front inside cover of this text?

Problem 29E The Modern View of Atomic Structure; Atomic Weights (Sections) (a) What isotope is used as the standard in establishing the atomic mass scale? (b) The atomic weight of boron is reported as 10.81, yet no atom of boron has the mass of 10.81 amu. Explain.

Problem 28E The Modern View of Atomic Structure; Atomic Weights (Sections) One way in which Earth’s evolution as a planet can be understood is by measuring the amounts of certain isotopes in rocks. One quantity recently measured is the ratio of 129Xe to 130Xe in some minerals. In what way do these two isotopes differ from one another? In what respects are they the same?

Problem 31E The Modern View of Atomic Structure; Atomic Weights (Sections) Only two isotopes of copper occur naturally, 63Cu (atomic mass = 62.9296 amu; abundance 69.17%) and 65Cu (atomic mass = 64.9278 amu; abundance 30.83%). Calculate the atomic weight (average atomic mass) of copper.

Problem 27E The Modern View of Atomic Structure; Atomic Weights (Sections) Write the correct symbol, with both superscript and subscript, for each of the following. Use the list of elements in the front inside cover as needed: (a) the isotope of platinum that contains 118 neutrons, (b) the isotope of krypton with mass number 84, (c) the isotope of arsenic with mass number 75, (d) the isotope of magnesium that has an equal number of protons and neutrons.

Problem 32E The Modern View of Atomic Structure; Atomic Weights (Sections) Rubidium has two naturally occurring isotopes, rubidium-85 (atomic mass = 84.9118 amu; abundance = 72.15%) and rubidium-87 (atomic mass = 86.909) amu; abundance = 27.85%). Calculate the atomic weight of rubidium.

The Modern View of Atomic Structure; Atomic Weights (Sections) Naturally occurring magnesium has the following isotopic abundances: (a) What is the average atomic mass of Mg? (b) Sketch the mass spectrum of Mg.

a) The mass spectrometer in Figure 2.12 has a magnet as one of its components. What is the purpose of the magnet? (b) The atomic weight of Cl is 35.5 amu. However, the mass spectrum of Cl (Figure 2.13) does not show a peak at this mass. Explain. (c) A mass spectrum of phosphorus (P) atoms shows only a single peak at a mass of 31. What can you conclude from this observation?

Problem 38E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Locate each of the following elements in the periodic table; give its name and atomic number, and indicate whether it is a metal, metalloid, or nonmetal: (a) Li, (b) Sc, (c) Ge, (d) Yb, (e) Mn, (f) Sb, (g) Xe.

Problem 36E The Modern View of Atomic Structure; Atomic Weights (Sections) Mass spectrometry is more often applied to molecules than to atoms. We will see in Chapter that the molecular weight of a molecule is the sum of the atomic weights of the atoms in the molecule. The mass spectrum of H2 is taken under conditions that prevent decomposition into H atoms. The two naturally occurring isotopes of hydrogen are 1H (atomic mass = 1.00783 amu; abundance 99.9885%) and 2H (atomic mass = 2.01410 amu; abundance 0.0115%). (a) How many peaks will the mass spectrum have? (b) Give the relative atomic masses of each of these peaks. (c) Which peak will be the largest, and which the smallest?

Problem 37E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) For each of the following elements, write its chemical symbol, locate it in the periodic table, give its atomic number, and indicate whether it is a metal, metalloid, or non-metal: (a) chromium, (b) helium, (c) phosphorus, (d) zinc, (e) magnesium, (f) bromine, (g) arsenic.

(a) In what fundamental way is mass spectrometry related to Thomson’s cathode-ray experiments (Figure 2.4)? (b) What are the labels on the axes of a mass spectrum? (c) To measure the mass spectrum of an atom, the atom must first lose one or more electrons. Why is this so

Problem 41E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) What can we tell about a compound when we know the empirical formula? What additional information is conveyed by the molecular formula? By the structural formula? Explain in each case.

Problem 39E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) For each of the following elements, write its chemical symbol, determine the name of the group to which it belongs (Table), and indicate whether it is a metal, metalloid, or nonmetal: Table Names of Some Groups in the Periodic Table Group Name Elements 1A Alkali metals Li, Na, K, Rb, Cs, Fr 2A Alkaline earth metals Be, Mg, Ca, Sr, Ba, Ra 6A Chalcogens O, S, Se, Te, Po 7A Halogens F, Cl, Br, I, At 8A Noble gases (or rare gases) He, Ne, Ar, Kr, Xe, Rn (a) potassium, (b) iodine, (c) magnesium, (d) argon, (e) sulfur.

Problem 40E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) The elements of group 4A show an interesting change in properties moving down the group. Give the name and chemical symbol of each element in the group and label it as a nonmetal, metalloid, or metal.

Problem 44E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Determine the molecular and empirical formulas of the following: (a) the organic solvent benzene, which has six carbon atoms and six hydrogen atoms; (b) the compound silicon tetrachloride, which has a silicon atom and four chlorine atoms and is used in the manufacture of computer chips; (c) the reactive substance diborane, which has two boron atoms and six hydrogen atoms; (d) the sugar called glucose, which has six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.

Problem 45E How many hydrogen atoms are in each of the following: (a) C2H5OH, (b) Ca(CH3COO)2, (c)(NH4)3PO4?

Problem 43E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Write the empirical formula corresponding to each of the following molecular formulas:(a) Al2Br6, (b) C8H10, (c) C4H8O2, (d) P4O10, (e) C6H4Cl2, (f) B3N3H6.

Problem 46E How many of the indicated atoms are represented by each chemical formula: (a) carbon atoms in C2H5COOCH3, (b) oxygen atoms in Ca(ClO4)2, (c) hydrogen atoms in (NH4)2HPO4?

Write the molecular and structural formulas for the compounds represented by the following molecular models:

Problem 42E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Two compounds have the same empirical formula. One substance is a gas, whereas the other is a viscous liquid. How is it possible for two substances with the same empirical formula to have markedly different properties?

Problem 49E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Fill in the gaps in the following table: Symbol 59Co3+ Protons 34 76 80 Neutrons 46 116 120 Electrons 36 78 Net charge 2+

Problem 50E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Fill in the gaps in the following table: Symbol 31Co3- Protons 34 50 Neutrons 45 69 118 Electrons 36 46 76 Net charge 2- 3+

Problem 51E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Each of the following elements is capable of forming an ion in chemical reactions. By referring to the periodic table, predict the charge of the most stable ion of each: (a) Mg, (b) Al, (c) K, (d) S, (e) F.

Problem 52E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Using the periodic table, predict the charges of the ions of the following elements: (a) Ga, (b) Sr, (c) As, (d) Br, (e) Se.

Problem 48E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Write the molecular and structural formulas for the compounds represented by the following models:

Problem 54E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) The most common charge associated with scandium in its compounds is 3+. Indicate the chemical formulas you would expect for compounds formed between scandium and (a) iodine, (b) sulphur, (c) nitrogen.

Problem 55E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Predict the chemical formula for the ionic compound formed by: (a) Ca2+ and Br-, (b) K+ and CO3 2-, (c) Al3+ and CH3COO-, (d) NH4 + and SO4 2-, (e) Mg2+ and PO4 3-.

Problem 58E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Complete the table by filling in the formula for the ionic compound formed by each pair of cations and anions, as shown for the first pair. Ion Na+ Ca2+ Fe2+ Al3+ O2- Na2O No3- SO42- Aso43-

Problem 59E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Predict whether each of the following compounds is molecular or ionic: (a) B2H6, (b) CH3OH, (c) LiNO3, (d) Sc2O3, (e) CsBr, (f) NOCl, (g) NF3, (h) Ag2SO4.,

Problem 56E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Predict the chemical formulas of the compounds formed by the following pairs of ions: (a) Cr3+and Br-, (b) Fe3+ and O2-, (c) Hg2 2+ and CO3 2-, (d) Ca2+ and ClO3-, (e) NH4 + and PO43-.

Problem 60E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Which of the following are ionic, and which are molecular? (a) PF5, (b) NaI, (c) SCl2, (d) Ca(NO3)2, (e) FeCl3, (f) LaP, (g) CoCO3, (h) N2O4.

Problem 57E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Complete the table by filling in the formula for the ionic compound formed by each pair of cations and anions, as shown for the first pair. Ion K+ NH4+ Mg2+ Fe3+ cl- KCl OH- Co32- po43-

Problem 61E Give the chemical formula for (a) chlorite ion, (b) chloride ion, (c) chlorate ion, (d) perchlorate ion, (e) hypochlorite ion.

Problem 62E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Selenium, an element required nutritionally in trace quantities, forms compounds analogous to sulfur. Name the following ions: (a) SeO4 2-, (b) Se2-, (c) HSe-, (d) HSeO3-.

Problem 63E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Give the names and charges of the cation and anion in each of the following compounds: (a) CaO, ________________ (b) Na2SO4, ________________ (c) KClO4, ________________ (d) Fe(NO3)2, ________________ (e) Cr(OH)3.

Problem 64E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Give the names and charges of the cation and anion in each of the following compounds: (a) CuS, (b) Ag2SO4, (c) Al(ClO3)3, (d) Co(OH)2, (e) PbCO3.

Problem 65E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Name the following ionic compounds: (a) Li2O, (b) FeCl3, (c) NaClO, (d) CaSO3, (e) Cu(OH)2, (f) Fe(NO3)2, (g) Ca(CH3COO)2, (h) Cr2(CO3)3, (i) K2CrO4, (j) (NH4)2SO4.

Problem 53E The Periodic Table, Molecules and Molecular Compounds, and Ions and Ionic Compounds (Sections) Using the periodic table to guide you, predict the chemical formula and name of the compound formed by the following elements: (a) Ga and F, (b) Li and H, (c) Al and I, (d) K and S.

Problem 66E Name the following ionic compounds: (a) KCN, (b) NaBrO2, (c) Sr(OH)2, (d) CoS, (e)Fe2(CO3)3, (f) Cr(NO3)3, (g) (NH4)2SO3, (h) NaH2PO4, (i) KMnO4, (j) Ag2Cr2O7.

Problem 71E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Give the name or chemical formula, as appropriate, for each of the following binary molecular substances: (a) SF6, (b) IF5, (c) XeO3, (d) dinitrogen tetroxide, (e) hydrogen cyanide, (f) tetraphosphorus hexasulfide.

Naming Inorganic Compounds; Some Simple Organic Compounds (Sections)Provide the name or chemical formula, as appropriate, for each of the following acids: (a) hydroiodic acid, (b) chloric acid, (c) nitrous acid, (d) H2CO3, (e) HClO4, (f) CH3COOH.

Problem 68E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Give the chemical formula for each of the following ionic compounds: (a) sodium phosphate, (b) zinc nitrate, (c) barium bromate, (d) iron(II) perchlorate, (e) cobalt(II) hydrogen carbonate, (f) chromium(III) acetate, (g) potassium dichromate.

Problem 69E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Give the name or chemical formula, as appropriate, for each of the following acids: (a) HBrO3, (b) HBr, (c) H3PO4, (d) hypochlorous acid, (e) iodic acid, (f) sulfurous acid.

Problem 67E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Write the chemical formulas for the following compounds: (a) aluminum hydroxide, (b) potassium sulfate, (c) copper(I) oxide, (d) zinc nitrate, (e) mercury(II) bromide, (f) iron(III) carbonate, (g) sodium hypobromite.

Problem 73E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Write the chemical formula for each substance mentioned in the following word descriptions (use the front inside cover to find the symbols for the elements you do not know). (a) Zinc carbonate can be heated to form zinc oxide and carbon dioxide.(b) On treatment with hydrofluoric acid, silicon dioxide forms silicon tetrafluoride and water. (c) Sulfur dioxide reacts with water to form sulfurous acid. (d) The substance phosphorus trihydride, commonly called phosphine, is a toxic gas. (e) Perchloric acid reacts with cadmium to form cadmium(II) perchlorate. (f) Vanadium(III) bromide is a colored solid.

(a) What is a hydrocarbon? (b) Butane is the alkane with a chain of four carbon atoms. Write a structural formula for this compound and determine its molecular and empirical formulas.

Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) The oxides of nitrogen are very important components in urban air pollution. Name each of the following compounds: (a) N2O, (b) NO, (c) NO2, (d) N2O5, (e) N2O4.

Assume that you encounter the following sentences in your reading. What is the chemical formula for each substance mentioned? (a) Sodium hydrogen carbonate is used as a deodorant. (b) Calcium hypochlorite is used in some bleaching solutions. (c) Hydrogen cyanide is a very poisonous gas. (d) Magnesium hydroxide is used as a cathartic. (e) Tin(II) fluoride has been used as a fluoride additive in toothpastes. (f) When cadmium sulfide is treated with sulfuric acid, fumes of hydrogen sulfide are given off.

(a) What ending is used for the names of alkanes? (b) Hexane is an alkane whose structural formula has all its carbon atoms in a straight chain. Draw the structural formula for this compound and determine its molecular and empirical formulas. (Hint: You might need to refer to Table 2.6.)

Problem 77E (a)What is a functional group? (b)What functional group characterizes an alcohol? (c) With reference to Exercise 2.75, write a structural formula for 1-butanol, the alcohol derived from butane, by making a substitution on one of the carbon atoms. Reference (a) What is a hydrocarbon? (b) Butane is the alkane with a chain of four carbon atoms. Write a structural formula for this compound and determine its molecular and empirical formulas.

(a) What do ethane and ethanol have in common? (b) How does 1-propanol differ from propane?

Problem 80E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Draw the structural formulas for three isomers of pentane, C5H12.

Problem 81AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Suppose a scientist repeats the Millikan oil-drop experiment but reports the charges on the drops using an unusual (and imaginary) unit called the warmomb (wa). The scientist obtains the following data for four of the drops: Droplet Calculated Charge (wa) A 3.84 × 10-8 B 4.80 × 10-8 C 2.88 × 10-8 D 8.64 × 10-8 (a) If all the droplets were the same size, which would fall most slowly through the apparatus? (b) From these data, what is the best choice for the charge of the electron in warmombs? (c) Based on your answer to part (b), how many electrons are there on each of the droplets? (d) What is the conversion factor between warmombs and coulombs?

Problem 83AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. A cube of gold that is 1.00 cm on a side has a mass of 19.3 g. A single gold atom has a mass of 197.0 amu. (a) How many gold atoms are in the cube? (b) From the information given, estimate the diameter in Å of a single gold atom. (c) What assumptions did you make in arriving at your answer for part (b)?

Problem 82AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. The natural abundance of 3He is 0.000137%. (a) How many protons, neutrons, and electrons are in an atom of 3He? (b) Based on the sum of the masses of their subatomic particles, which is expected to be more massive, an atom of 3He or an atom of 3H (which is also called tritium)? (c) Based on your answer to part (b), what would need to be the precision of a mass spectrometer that is able to differentiate between peaks that are due to 3He+ and 3H+?

The diameter of a rubidium atom is . We will consider two different ways of placing the atoms on a surface. In arrangement A, all the atoms are lined up with one another to form a square grid. Arrangement B is called a close-packed arrangement because the atoms sit in the “depressions” formed by the previous row of atoms: (a) Using arrangement A, how many Rb atoms could be placed on a square surface that is 1.0 cm on a side? (b) How many Rb atoms could be placed on a square surface that is 1.0 cm on a side, using arrangement B? (c) By what factor has the number of atoms on the surface increased in going to arrangement B from arrangement A? If extended to three dimensions, which arrangement would lead to a greater density for Rb metal?

Problem 86AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Identify the element represented by each of the following symbols and give the number of protons and neutrons in each: (a) 74 33X, (b) 127 53 X, (c) 152 63 X, (d) 209 83 X.

(a) Assuming the dimensions of the nucleus and atom shown in Figure 2.11, what fraction of the volume of the atom is taken up by the nucleus? (b) Using the mass of the proton from Table 2.1 and assuming its diameter is 1.0 X 10-15 m, calculate the density of a proton in g/cm3.

Problem 79E Naming Inorganic Compounds; Some Simple Organic Compounds (Sections) Chloropropane is derived from propane by substituting Cl for H on one of the carbon atoms. (a) Draw the structural formulas for the two isomers of chloropropane. (b) Suggest names for these two compounds.

Problem 89AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. The element lead (Pb) consists of four naturally occurring isotopes with atomic masses 203.97302, 205.97444, 206.97587, and 207.97663 amu. The relative abundances of these four isotopes are 1.4, 24.1, 22.1, and 52.4% respectively. From these data, calculate the atomic weight of lead.

Use Coulomb's law, , to calculate the electric force on an electron exerted by a single proton if the particles are apart. The constant in Coulomb's law is . (The unit abbreviated is the newton, the SI unit of force.)

Problem 87AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. The element oxygen has three naturally occurring isotopes, with 8, 9, and 10 neutrons in the nucleus, respectively. (a) Write the full chemical symbols for these three isotopes. (b) Describe the similarities and differences between the three kinds of atoms of oxygen.

Problem 92AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. There are two different isotopes of bromine atoms. Under normal conditions, elemental bromine consists of Br2 molecules, and the mass of a Br2 molecule is the sum of the masses of the two atoms in the molecule. The mass spectrum of Br2 consists of three peaks: Mass (amu) Relative Size 157.836 0.2569 159.834 0.4999 161.832 0.2431 (a) What is the origin of each peak (of what isotopes does each consist)? (b) What is the mass of each isotope? (c) Determine the average molecular mass of a Br2 molecule. (d) Determine the average atomic mass of a bromine atom. (e) Calculate the abundances of the two isotopes.

These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Gallium (Ga) consists of two naturally occurring isotopes with masses of 68.926 and 70.925 amu. (a) How many protons and neutrons are in the nucleus of each isotope? Write the complete atomic symbol for each, showing the atomic number and mass number. (b) The average atomic mass of Ga is 69.72 amu. Calculate the abundance of each isotope.

Problem 93AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. It is common in mass spectrometry to assume that the mass of a cation is the same as that of its parent atom. (a) Using data in Table, determine the number of significant figures that must be reported before the difference in masses of 1H and 1H+ is significant. Table Comparison of the Proton, Neutron, and Electron Particle Charge Mass (amu) Proton Positive (1+) 1.0073 Neutron None (neutral) 1.0087 Electron Negative (1—) 5.486 × 10-4 , ________________ (b) What percentage of the mass of an 1H atom does the electron represent?

Problem 95AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. The first atoms of seaborgium (Sg) were identified in 1974. The longest-lived isotope of Sg has a mass number of 266. (a) How many protons, electrons, and neutrons are in an 266Sg atom? (b) Atoms of Sg are very unstable, and it is therefore difficult to study this element’s properties. Based on the position of Sg in the periodic table, what element should it most closely resemble in its chemical properties?

Problem 96AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. The explosion of an atomic bomb releases many radioactive isotopes, including strontium-90. Considering the location of strontium in the periodic table, suggest a reason for the fact that this isotope is particularly dangerous for human health.

Problem 91AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Using a suitable reference such as the CRC Handbook of Chemistry and Physicsorhttp://www.webelements.com, look up the following information for nickel: (a) the number of known isotopes, (b) the atomic masses (in amu), (c) the natural abundances of the five most abundant isotopes.

Problem 94AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. From the following list of elements—Ar, H, Ga, Al, Ca, Br, Ge, K, O—pick the one that best fits each description. Use each element only once: (a) an alkali metal, (b) an alkaline earth metal, (c) a noble gas, (d) a halogen, (e) a metalloid, (f) a nonmetal listed in group 1A, (g) a metal that forms a 3+ ion, (h) a nonmetal that forms a 2-ion, (i) an element that resembles aluminum.

These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. From the molecular structures shown here, identify the one that corresponds to each of the following species: (a) chlorine gas, (b) propane, (c) nitrate ion, (d) sulfur trioxide, (e) methyl chloride, CH3Cl.

Problem 99AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Fill in the blanks in the following table: Cation Anion Formula Name Lithium oxide Fe2+ po43- Al2(so4)3 Copper(II) nitrate Cr3+ I- MnClO2 Ammonium carbonate Zinc perchlorate

Problem 101AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Elements in the same group of the periodic table often form oxyanions with the same general formula. The anions are also named in a similar fashion. Based on these observations, suggest a chemical formula or name, as appropriate, for each of the following ions: (a) BrO4 –, (b) SeO3 2-, (c) arsenate ion, (d) hydrogen tellurate ion.

Problem 100AE Iodic acid has the molecular formula HIO3.Write the formulas for the following: (a) the iodate anion, (b) the periodate anion, (c) the hypoiodite anion, (d) hypoiodous acid, (e) periodic acid.

Problem 103AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Give the chemical names of each of the following familiar compounds: (a) NaCl (table salt), (b) NaHCO3 (baking soda), (c) NaOCl (in many bleaches), (d) NaOH (caustic soda), (e) (NH4)2CO3 (smelling salts), (f) CaSO4 (plaster of Paris).

Problem 98AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Name each of the following oxides. Assuming that the compounds are ionic, what charge is associated with the metallic element in each case? (a) NiO, (b) MnO2, (c) Cr2O3, (d) MoO3.,

Problem 102AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Carbonic acid occurs in carbonated beverages. When allowed to react with lithium hydroxide, it produces lithium carbonate. Lithium carbonate is used to treat depression and bipolar disorder. Write chemical formulas for carbonic acid, lithium hydroxide, and lithium carbonate.

Problem 104AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Many familiar substances have common, unsystematic names. For each of the following, give the correct systematic name: (a) saltpeter, KNO3, (b) soda ash, Na2CO3, (c) lime, CaO, (d) muriatic acid, HCl, (e) Epsom salts, MgSO4, (f) milk of magnesia, Mg(OH)2.

Problem 105AE These exercises are not divided by category, although they are roughly in the order of the topics in the chapter. They are not paired. Because many ions and compounds have very similar names, there is great potential for confusing them. Write the correct chemical formulas to distinguish between (a) calcium sulfide and calcium hydrogen sulfide, (b) hydrobromic acid and bromic acid, (c) aluminum nitride and aluminum nitrite, (d) iron(II) oxide and iron(III) oxide, (e) ammonia and ammonium ion, (f) potassium sulfite and potassium bisulfite, (g) mercurous chloride and mercuric chloride, (h) chloric acid and perchloric acid.

The compound cyclohexane is an alkane in which six carbon atoms form a ring. The partial structural formula of the compound is as follows: (a) Complete the structural formula for cyclohexane.(b) Is the molecular formula for cyclohexane the same as that for n-hexane, in which the carbon atoms are in a straight line? If possible, comment on the source of any differences. (c) Propose a structural formula for cyclohexanol, the alcohol derived from cyclohexane.

Problem 1E Visualizing Concepts These exercises are intended to probe your understanding of key concepts rather than your ability to utilize formulas and perform calculations. Exercises with red numbers have answers in the back of the book. A charged particle is caused to move between two electrically charged plates, as shown here. (a) Why does the path of the charged particle bend? (b) What is the sign of the electrical charge on the particle? (c) As the charge on the plates is increased, would you expect the bending to increase, decrease, or stay the same? (d) As the mass of the particle is increased while the speed of the particles remains the same, would you expect the bending to increase, decrease, or stay the same? [Section]

Problem 1PE Atomic Size The diameter of a U.S. dime is 17.9 mm, and the diameter of a silver atom is 2.88 Å. How many silver atoms could be arranged side by side across the diameter of a dime? The diameter of a carbon atom is 1.54 Å. (a) Express this diameter in picometers. (b) How many carbon atoms could be aligned side by side across the width of a pencil line that is 0.20 mm wide?

The following diagram is a representation of 20 atoms of a fictitious element, which we will call nevadium (Nv). The red spheres are 293Nv, and the blue spheres are 295Nv. (a) Assuming that this sample is a statistically representative sample of the element, calculate the percent abundance of each element. (b) If the mass of 293Nv is 293.15 amu and that of 295Nv is 295.15 amu, what is the atomic weight of Nv? [Section 2.4]

Problem 2PE Determining the Number of Subatomic Particles in Atoms How many protons, neutrons, and electrons are in an atom of (a) 197Au, (b) strontium-90? How many protons, neutrons, and electrons are in an atom of (a) 138Ba, (b) phosphorus-31?

Problem 3E Visualizing Concepts These exercises are intended to probe your understanding of key concepts rather than your ability to utilize formulas and perform calculations. Exercises with red numbers have answers in the back of the book. Four of the boxes in the following periodic table are colored. Which of these are metals and which are nonmetals? Which one is an alkaline earth metal? Which one is a noble gas? [Section]

Problem 3PE Writing Symbols for Atoms Magnesium has three isotopes with mass numbers 24, 25, and 26. (a) Write the complete chemical symbol (superscript and subscript) for each. (b) How many neutrons are in an atom of each isotope? Give the complete chemical symbol for the atom that contains 82 protons, 82 electrons, and 126 neutrons.

Does the following drawing represent a neutral atom or an ion? Write its complete chemical symbol including mass number, atomic number, and net charge (if any). [Sections 2.3 and 2.7]

Problem 4PE Calculating the Atomic Weight of an Element from Isotopic Abundances Naturally occurring chlorine is 75.78% 35Cl (atomic mass 34.969 amu) and 24.22% 37Cl (atomic mass 36.966 amu). Calculate the atomic weight of chlorine. Three isotopes of silicon occur in nature: 28Si (92.23%), atomic mass 27.97693 amu; 29Si (4.68%), atomic mass 28.97649 amu; and 30Si (3.09%), atomic mass 29.97377 amu. Calculate the atomic weight of silicon.

Problem 5E Visualizing Concepts These exercises are intended to probe your understanding of key concepts rather than your ability to utilize formulas and perform calculations. Exercises with red numbers have answers in the back of the book. Which of the following diagrams most likely represents an ionic compound, and which represents a molecular one? Explain your choice. [Sections]

Problem 5PE Using the Periodic Table Which two of these elements would you expect to show the greatest similarity in chemical and physical properties: B, Ca, F, He, Mg, P? Locate Na (sodium) and Br (bromine) in the periodic table. Give the atomic number of each and classify each as metal, metalloid, or nonmetal.

Problem 6E Visualizing Concepts These exercises are intended to probe your understanding of key concepts rather than your ability to utilize formulas and perform calculations. Exercises with red numbers have answers in the back of the book. Write the chemical formula for the following compound. Is the compound ionic or molecular? Name the compound. [Sections]

Problem 6PE Give the empirical formula for diborane, whose molecular formula is B2H6.

Problem 7E Visualizing Concepts These exercises are intended to probe your understanding of key concepts rather than your ability to utilize formulas and perform calculations. Exercises with red numbers have answers in the back of the book. Five of the boxes in the following periodic table are colored. Predict the charge on the ion associated with each of these elements. [Section]

Problem 7PE Writing Chemical Symbols for Ions Give the chemical symbol, including superscript indicating mass number, for (a) the ion with 22 protons, 26 neutrons, and 19 electrons; and (b) the ion of sulfur that has 16 neutrons and 18 electrons. How many protons, neutrons, and electrons does the 79Se2- ion possess?

Problem 8E Visualizing Concepts These exercises are intended to probe your understanding of key concepts rather than your ability to utilize formulas and perform calculations. Exercises with red numbers have answers in the back of the book. The following diagram represents an ionic compound in which the red spheres represent cations and blue spheres represent anions. Which of the following formulas is consistent with the drawing? KBr, K2SO4, Ca(NO3)2, Fe2(SO4)3. Name the compound. [Sections]

Problem 8PE Predicting Ionic Charge Predict the charge expected for the most stable ion of barium and the most stable ion of oxygen. Predict the charge expected for the most stable ion of (a) aluminum and (b) fluorine.

The Atomic Theory of Matter and the Discovery of Atomic Structure (Sections) How does Dalton’s atomic theory account for the fact that when 1.000 g of water is decomposed into its elements, 0.111 g of hydrogen and 0.889 g of oxygen are obtained regardless of the source of the water?

Problem 9PE Identifying Ionic and Molecular Compounds Which of these compounds would you expect to be ionic: N2O, Na2O, CaCl2, SF4? Which of these compounds are molecular: CBr4, FeS, P4O6, PbF2?

Problem 10E The Atomic Theory of Matter and the Discovery of Atomic Structure (Sections) Hydrogen sulfide is composed of two elements: hydrogen and sulfur. In an experiment, 6.500 g of hydrogen sulfide is fully decomposed into its elements. (a) If 0.384 g of hydrogen is obtained in this experiment, how many grams of sulfur must be obtained? (b) What fundamental law does this experiment demonstrate? (c) How is this law explained by Dalton’s atomic theory?

Problem 10PE Using Ionic Charge to Write Empirical Formulas for Ionic Compounds Write the empirical formula of the compound formed by (a) Al3+ and Cl- ions, (b) Al3+ and O2-ions, (c) Mg2+ and NO-3 ions. Write the empirical formula for the compound formed by (a) Na+ and PO43-, (b) Zn2+ and SO42-, (c) Fe3+ and CO32-.

Problem 11E The Atomic Theory of Matter and the Discovery of Atomic Structure (Sections) A chemist finds that 30.82 g of nitrogen will react with 17.60, 35.20, 70.40, or 88.00 g of oxygen to form four different compounds. (a) Calculate the mass of oxygen per gram of nitrogen in each compound. (b) How do the numbers in part (a) support Dalton’s atomic theory?

The formula for the bromate ion is analogous to that for the chlorate ion. Write the formula for the hypobromite and bromite ions.

Problem 12E The Atomic Theory of Matter and the Discovery of Atomic Structure (Sections) In a series of experiments, a chemist prepared three different compounds that contain only iodine and fluorine and determined the mass of each element in each compound: Compound Mass of Iodine (g) Mass of Fluorine (g) 1 4.75 3.56 2 7.64 3.43 3 9.41 9.86 (a) Calculate the mass of fluorine per gram of iodine in each compound. (b) How do the numbers in part (a) support the atomic theory?

Problem 12PE Determining the Names of Ionic Compounds from Their Formulas Name the ionic compounds (a) K2SO4, (b) Ba(OH)2, (c) FeCl3. Name the ionic compounds (a) NH4Br, (b) Cr2O3, (c) Co(NO3)2.

Problem 13E The Atomic Theory of Matter and the Discovery of Atomic Structure (Sections) Summarize the evidence used by J. J. Thomson to argue that cathode rays consist of negatively charged particles.

Problem 13PE Give the chemical formulas for (a) magnesium sulfate, (b) silver sulfide, (c) lead(II) nitrate.

An unknown particle is caused to move between two electrically charged plates, as illustrated in Figure 2.8. Its path is deflected by a smaller magnitude in the opposite direction from that of a beta particle. What can you conclude about the charge and mass of this unknown particle?

Problem 14PE Relating the Names and Formulas of Acids Name the acids (a) HCN, (b) HNO3, (c) H2SO4, (d) H2SO3. Give the chemical formulas for (a) hydrobromic acid, (b) carbonic acid.

Problem 15E The Atomic Theory of Matter and the Discovery of Atomic Structure (Sections) How did Rutherford interpret the following observations made during his ?-particle scattering experiments? (a) Most a particles were not appreciably deflected as they passed through the gold foil. (b) A few a particles were deflected at very large angles. (c) What differences would you expect if beryllium foil were used instead of gold foil in the ?-particle scattering experiment?