Solution: The early alchemists used to do an experiment in

The following data were collected for several compounds of nitrogen and oxygen: Mass of Nitrogen That Combines with 1 g of Oxygen Compound A 1.750 g Compound B 0.8750 g Compound C 0.4375 g Show how these data illustrate the law of multiple proportions.

You have learned about three different models of the atom: Daltons model, Thomsons model, and Rutherfords model. What if Dalton was correct? What would Rutherford have expected from his experiments with gold foil? What if Thomson was correct? What would Rutherford have expected from his experiments with gold foil?

The average diameter of an atom is 2 3 10210 m. What if the average diameter of an atom were 1 cm? How tall would you be?

Write the symbol for the atom that has an atomic number of 9 and a mass number of 19. How many electrons and how many neutrons does this atom have?

Name each binary compound. a. CsF b. AlCl3 c. LiH

Given the following systematic names, write the formula for each compound: a. potassium iodide b. calcium oxide c. gallium bromide

Give the systematic name for each of the following compounds: a. CuCl b. HgO c. Fe2O3

Given the following systematic names, write the formula for each compound: a. Manganese(IV) oxide b. Lead(II) chloride

We can use the periodic table to tell us something about the stable ions formed by many atoms. For example, the atoms in column 1 always form 11 ions. The transition metals, however, can form more than one type of stable ion. What if each transition metal ion had only one possible charge? How would the naming of compounds be different?

Give the systematic name for each of the following compounds: a. CoBr2 b. CaCl2 c. Al2O3

Given the following systematic names, write the formula for each compound: a. Chromium(III) chloride b. Gallium iodide

Give the systematic name for each of the following compounds: a. Na2SO4 d. Mn(OH)2 b. KH2PO4 e. Na2SO3 c. Fe(NO3)3 f. Na2CO3

Given the following systematic names, write the formula for each compound: a. Sodium hydrogen carbonate b. Cesium perchlorate c. Sodium hypochlorite d. Sodium selenate e. Potassium bromate

Name each of the following compounds: a. PCl5 b. PCl3 c. SO2

From the following systematic names, write the formula for each compound: a. Sulfur hexafluoride b. Sulfur trioxide c. Carbon dioxide

Give the systematic name for each of the following compounds: a. P4O10 b. Nb2O5 c. Li2O2 d. Ti(NO3)4

Given the following systematic names, write the formula for each compound: a. Vanadium(V) fluoride b. Dioxygen difluoride c. Rubidium peroxide d. Gallium oxide

In this chapter, you have learned a systematic way to name chemical compounds. What if all compounds had only common names? What problems would this cause?

Use Daltons atomic theory to account for each of the following. a. the law of conservation of mass b. the law of definite proportion c. the law of multiple proportions

What evidence led to the conclusion that cathode rays had a negative charge?

What discoveries were made by J. J. Thomson, Henri Becquerel, and Lord Rutherford? How did Daltons model of the atom have to be modified to account for these discoveries?

Consider Ernest Rutherfords a-particle bombardment experiment illustrated in Fig. 2.12. How did the results of this experiment lead Rutherford away from the plum pudding model of the atom to propose the nuclear model of the atom?

Do the proton and the neutron have exactly the same mass? How do the masses of the proton and neutron compare to the mass of the electron? Which particles make the greatest contribution to the mass of an atom?Which particles make the greatest contribution to the chemical properties of an atom

What is the distinction between atomic number and mass number? Between mass number and atomic mass?

Distinguish between the terms family and period in connection with the periodic table. For which of these terms is the term group also used?

The compounds AlCl3, CrCl3, and ICl3 have similar formulas, yet each follows a different set of rules to name it. Name these compounds, and then compare and contrast the nomenclature rules used in each case.

When metals react with nonmetals, an ionic compound generally results. What is the predicted general formula for the compound formed between an alkali metal and sulfur? Between an alkaline earth metal and nitrogen? Between aluminum and a halogen?

How would you name HBrO4, KIO3, NaBrO2, and HIO? Refer to Table 2.5 and the acid nomenclature discussion in the text.

Which of the following is true about an individual atom? Explain. a. An individual atom should be considered to be a solid. b. An individual atom should be considered to be a liquid. c. An individual atom should be considered to be a gas. d. The state of the atom depends on which element it is. e. An individual atom cannot be considered to be a solid, liquid, or gas. Justify your choice, and for choices you did not pick, explain what is wrong with them.

How would you go about finding the number of chalk molecules it takes to write your name on the board? Provide an explanation of all you would need to do and a sample calculation.

These questions concern the work of J. J. Thomson. a. From Thomsons work, which particles do you think he would feel are most important for the formation of compounds (chemical changes) and why? b. Of the remaining two subatomic particles, which do you place second in importance for forming compounds and why? c. Propose three models that explain Thomsons findings and evaluate them. To be complete you should include Thomsons findings.

Heat is applied to an ice cube in a closed container until only steam is present. Draw a representation of this process, assuming you can see it at an extremely high level of magnification. What happens to the size of the molecules? What happens to the total mass of the sample?

You have a chemical in a sealed glass container filled with air. The setup is sitting on a balance as shown below. The chemical is ignited by means of a magnifying glass focusing sunlight on the reactant. After the chemical has completely burned, which of the following is true? Explain your answer. 250.0 g a. The balance will read less than 250.0 g. b. The balance will read 250.0 g. c. The balance will read greater than 250.0 g. d. Cannot be determined without knowing the identity of the chemical.

The formula of water is H2O. Which of the following is indicated by this formula? Explain your answer. a. The mass of hydrogen is twice that of oxygen in each molecule. b. There are two hydrogen atoms and one oxygen atom per water molecule. c. The mass of oxygen is twice that of hydrogen in each molecule. d. There are two oxygen atoms and one hydrogen atom per water molecule

You may have noticed that when water boils, you can see bubbles that rise to the surface of the water. Which of the following is inside these bubbles? Explain. a. air b. hydrogen and oxygen gas c. oxygen gas d. water vapor e. carbon dioxide gas

One of the best indications of a useful theory is that it raises more questions for further experimentation than it originally answered. Does this apply to Daltons atomic theory? Give examples

Dalton assumed that all atoms of the same element were identical in all their properties. Explain why this assumption is not valid.

Evaluate each of the following as an acceptable name for water: a. dihydrogen oxide c. hydrogen hydroxide b. hydroxide hydride d. oxygen dih

Why do we call Ba(NO3)2 barium nitrate, but we call Fe(NO3)2 iron(II) nitrate?

Why is calcium dichloride not the correct systematic name for CaCl2?

The common name for NH3 is ammonia. What would be the systematic name for NH3? Support your answer.

Which (if any) of the following can be determined by knowing the number of protons in a neutral element? Explain your answer. a. the number of neutrons in the neutral element b. the number of electrons in the neutral element c. the name of the elemen

Which of the following explain how an ion is formed? Explain your answer. a. adding or subtracting protons to/from an atom b. adding or subtracting neutrons to/from an atom c. adding or subtracting electrons to/from an atom

What refinements had to be made in Daltons atomic theory to account for Gay-Lussacs results on the combining volumes of gases?

When hydrogen is burned in oxygen to form water, the composition of water formed does not depend on the amount of oxygen reacted. Interpret this in terms of the law of definite proportion.

The two most reactive families of elements are the halogens and the alkali metals. How do they differ in their reactivities?

Explain the law of conservation of mass, the law of definite proportion, and the law of multiple proportions.

Section 2.3 describes the postulates of Daltons atomic theory. With some modifications, these postulates hold up very well regarding how we view elements, compounds, and chemical reactions today. Answer the following questions concerning Daltons atomic theory and the modifications made today. a. The atom can be broken down into smaller parts. What are the smaller parts? b. How are atoms of hydrogen identical to each other, and how can they be different from each other? c. How are atoms of hydrogen different from atoms of helium? How can H atoms be similar to He atoms? d. How is water different from hydrogen peroxide (H2O2) even though both compounds are composed of only hydrogen and oxygen? e. What happens in a chemical reaction, and why is mass conserved in a chemical reaction?

The contributions of J. J. Thomson and Ernest Rutherford led the way to todays understanding of the structure of the atom. What were their contributions?

What is the modern view of the structure of the atom?

The number of protons in an atom determines the identity of the atom. What does the number and arrangement of the electrons in an atom determine? What does the number of neutrons in an atom determine?

If the volume of a proton were similar to the volume of an electron, how will the densities of these two particles compare to each other?

For lighter, stable isotopes, the ratio of the mass number to the atomic number is close to a certain value. What is the value? What happens to the value of the mass number to atomic number ratio as stable isotopes become heavier?

List some characteristic properties that distinguish the metallic elements from the nonmetallic elements

Consider the elements of Group 4A (the carbon family): C, Si, Ge, Sn, and Pb. What is the trend in metallic character as one goes down this group? What is the trend in metallic character going from left to right across a period in the periodic table?

Distinguish between the following terms. a. molecule versus ion b. covalent bonding versus ionic bonding c. molecule versus compound d. anion versus cation

Label the type of bonding for each of the following. a. b.

The vitamin niacin (nicotinic acid, C6H5NO2) can be isolated from a variety of natural sources such as liver, yeast, milk, and whole grain. It also can be synthesized from commercially available materials. From a nutritional point of view, which source of nicotinic acid is best for use in a multivitamin tablet? Why?

Which of the following statements is(are) true? For the false statements, correct them. a. Most of the known elements are metals. b. Element 118 should be a nonmetal. c. Hydrogen has mostly metallic properties. d. A family of elements is also known as a period of elements. e. When an alkaline earth metal, A, reacts with a halogen, X, the formula of the covalent compound formed should be A2X.

Each of the following compounds has three possible names listed for it. For each compound, what is the correct name and why arent the other names used? a. N2O: nitrogen oxide, nitrogen(I) oxide, dinitrogen monoxide b. Cu2O: copper oxide, copper(I) oxide, dicopper monoxide c. Li2O: lithium oxide, lithium(I) oxide, dilithium monoxid

When mixtures of gaseous H2 and gaseous Cl2 react, a product forms that has the same properties regardless of the relative amounts of H2 and Cl2 used a. How is this result interpreted in terms of the law of definite proportion? b. When a volume of H2 reacts with an equal volume of Cl2 at the same temperature and pressure, what volume of product having the formula HCl is formed?

Observations of the reaction between nitrogen gas and hydrogen gas show us that 1 volume of nitrogen reacts with 3 volumes of hydrogen to make 2 volumes of gaseous product, as shown below: N N + HH HH HH Determine the formula of the product and justify your answer.

A sample of chloroform is found to contain 12.0 g of carbon, 106.4 g of chlorine, and 1.01 g of hydrogen. If a second sample of chloroform is found to contain 30.0 g of carbon, what is the total mass of chloroform in the second sample?

A sample of H2SO4 contains 2.02 g of hydrogen, 32.07 g of sulfur, and 64.00 g of oxygen. How many grams of sulfur and grams of oxygen are present in a second sample of H2SO4 containing 7.27 g of hydrogen?

Hydrazine, ammonia, and hydrogen azide all contain only nitrogen and hydrogen. The mass of hydrogen that combines with 1.00 g of nitrogen for each compound is 1.44 3 1021 g, 2.16 3 1021 g, and 2.40 3 1022 g, respectively. Show how these data illustrate the law of multiple proportions

Consider 100.0-g samples of two different compounds consisting only of carbon and oxygen. One compound contains 27.2 g of carbon and the other has 42.9 g of carbon. How can these data support the law of multiple proportions if 42.9 is not a multiple of 27.2? Show that these data support the law of multiple proportions

The three most stable oxides of carbon are carbon monoxide (CO), carbon dioxide (CO2), and carbon suboxide (C3O2). The molecules can be represented as Explain how these molecules illustrate the law of multiple proportions.

Two elements, R and Q, combine to form two binary compounds. In the first compound, 14.0 g of R combines with 3.00 g of Q. In the second compound, 7.00 g of R combines with 4.50 g of Q. Show that these data are in accord with the law of multiple proportions. If the formula of the second compound is RQ, what is the formula of the first compound?

In Section 1.1 of the text, the concept of a chemical reaction was introduced with the example of the decomposition of water, represented as follows: one oxygen molecule written O2 two water molecules written 2H2O electric current two hydrogen molecules written 2H2 Use ideas from Daltons atomic theory to explain how the above representation illustrates the law of conservation of mass.

In a combustion reaction, 46.0 g of ethanol reacts with 96.0 g of oxygen to produce water and carbon dioxide. If 54.0 g of water is produced, what mass of carbon dioxide is produced?

Early tables of atomic weights (masses) were generated by measuring the mass of a substance that reacts with 1.00 g of oxygen. Given the following data and taking the atomic mass of hydrogen as 1.00, generate a table of relative atomic masses for oxygen, sodium, and magnesium. Element Mass That Combines with 1.00 g Oxygen Assumed Formula Hydrogen 0.126 g HO Sodium 2.875 g NaO Magnesium 1.500 g MgO How do your values compare with those in the periodic table? How do you account for any differences?

Indium oxide contains 4.784 g of indium for every 1.000 g of oxygen. In 1869, when Mendeleev first presented his version of the periodic table, he proposed the formula In2O3 for indium oxide. Before that time it was thought that the formula was InO. What values for the atomic mass of indium are obtained using these two formulas? Assume that oxygen has an atomic mass of 16.00.

From the information in this chapter on the mass of the proton, the mass of the electron, and the sizes of the nucleus and the atom, calculate the densities of a hydrogen nucleus and a hydrogen atom.

If you wanted to make an accurate scale model of the hydrogen atom and decided that the nucleus would have a diameter of 1 mm, what would be the diameter of the entire model?

In an experiment it was found that the total charge on an oil drop was 5.93 3 10218 C. How many negative charges does the drop contain?

A chemist in a galaxy far, far away performed the Millikan oil drop experiment and got the following results for the charges on various drops. Use these data to calculate the charge of the electron in zirkombs. 2.56 3 10212 zirkombs 7.68 3 10212 zirkombs 3.84 3 10212 zirkombs 6.40 3 10213 zirkombs

What are the symbols of the following metals: sodium, radium, iron, gold, manganese, lead?

What are the symbols of the following nonmetals: fluorine, chlorine, bromine, sulfur, oxygen, phosphorus?

Give the names of the metals that correspond to the following symbols: Sn, Pt, Hg, Mg, K, Ag

Give the names of the nonmetals that correspond to the following symbols: As, I, Xe, He, C, Si.

a. Classify the following elements as metals or nonmetals: Mg Si Rn Ti Ge Eu Au B Am Bi At Br b. The distinction between metals and nonmetals is really not a clear one. Some elements, called metalloids, are intermediate in their properties. Which of these elements would you reclassify as metalloids? What other elements in the periodic table would you expect to be metalloids?

a. List the noble gas elements. Which of the noble gases has only radioactive isotopes? (This situation is indicated on most periodic tables by parentheses around the mass of the element. See inside front cover.) b. Which lanthanide element has only radioactive isotopes?

For each of the following sets of elements, label each as either noble gases, halogens, alkali metals, alkaline earth metals, or transition metals. a. Ti, Fe, Ag b. Mg, Sr, Ba c. Li, K, Rb d. Ne, Kr, Xe e. F, Br, I

Identify the elements that correspond to the following atomic numbers. Label each as either a noble gas, a halogen, an alkali metal, an alkaline earth metal, a transition metal, a lanthanide metal, or an actinide metal. a. 17 e. 2 b. 4 f. 92 c. 63 g. 55 d. 72

Write the atomic symbol (A ZX) for each of the following isotopes. a. Z 5 8, number of neutrons 5 9 b. the isotope of chlorine in which A 5 37 c. Z 5 27, A 5 60 d. number of protons 5 26, number of neutrons 5 31 e. the isotope of I with a mass number of 131 f. Z 5 3, number of neutrons 5 4

Write the atomic symbol (A ZX) for each of the isotopes described below. a. number of protons 5 27, number of neutrons 5 31 b. the isotope of boron with mass number 10 c. Z 5 12, A 5 23 d. atomic number 53, number of neutrons 5 79 e. Z 5 20, number of neutrons 5 27 f. number of protons 5 29, mass number 65

Write the symbol of each atom using the Z A X format. Nucleus 10 electrons a. 11 protons 12 neutrons Nucleus 11 electrons 9 protons 10 neutrons b. Nucleus 8 electrons c. 8 protons 8 neutrons

For carbon-14 and carbon-12, how many protons and neutrons are in each nucleus? Assuming neutral atoms, how many electrons are present in an atom of carbon-14 and in an atom of carbon-12?

How many protons and neutrons are in the nucleus of each of the following atoms? In a neutral atom of each element, how many electrons are present? a. 79Br d. 133Cs b. 81Br e. 3 H c. 239Pu f. 56Fe

What number of protons and neutrons are contained in the nucleus of each of the following atoms? Assuming each atom is uncharged, what number of electrons are present? a. 235 92U d. 208 82Pb b. 2 1 7 3Al e. 86 37Rb c. 57 26Fe f. 41 20Ca

For each of the following ions, indicate the number of protons and electrons the ion contains. a. Ba21 e. Co31 b. Zn21 f. Te22 c. N32 g. Br2 d. Rb

How many protons, neutrons, and electrons are in each of the following atoms or ions? a. 24 12Mg d. 59 27Co31 g. 79 34Se22 b. 24 12Mg21 e. 59 27Co h. 63 28Ni c. 59 27Co21 f. 79 34Se i. 59 28Ni2

What is the symbol for an ion with 63 protons, 60 electrons, and 88 neutrons? If an ion contains 50 protons, 68 neutrons, and 48 electrons, what is its symbol?

What is the symbol of an ion with 16 protons, 18 neutrons, and 18 electrons? What is the symbol for an ion that has 16 protons, 16 neutrons, and 18 electrons?

Complete the following table: Symbol Number of Protons in Nucleus Number of Neutrons in Nucleus Number of Electrons Net Charge 23 9 8 2U 20 20 21 23 28 20 8 3 9 9Y 35 44 36 15 16 32 68. Complete the following table: Symbol Number of Protons in Nucleus Number of Neutrons in Nucleus Number of Electrons Net Charge 5 2 3 6Fe21 26 33 31 85 125 86 13 14 10 76 54 22

Would you expect each of the following atoms to gain or lose electrons when forming ions? What ion is the most likely in each case? a. Ra c. P e. Br b. In d. Te f. Rb

For each of the following atomic numbers, use the periodic table to write the formula (including the charge) for the simple ion that the element is most likely to form in ionic compounds. a. 13 c. 56 e. 87 b. 34 d. 7 f. 35

Name the compounds in parts ad and write the formulas for the compounds in parts eh. a. NaBr e. strontium fluoride b. Rb2O f. aluminum selenide c. CaS g. potassium nitride d. AlI3 h. magnesium phosphid

Name the compounds in parts ad and write the formulas for the compounds in parts eh. a. Hg2O e. tin(II) nitride b. FeBr3 f. cobalt(III) iodide c. CoS g. mercury(II) oxide d. TiCl4 h. chromium(VI) sulfide

Name each of the following compounds: a. CsF c. Ag2S e. TiO2 b. Li3N d. MnO2 f. Sr3P2

Write the formula for each of the following compounds: a. zinc chloride d. aluminum sulfide b. tin(IV) fluoride e. mercury(I) selenide c. calcium nitride f. silver iodide

Name each of the following compounds: a. BaSO3 c. KMnO4 b. NaNO2 d. K2Cr2O7

Write the formula for each of the following compounds: a. chromium(III) hydroxide c. lead(IV) carbonate b. magnesium cyanide d. ammonium acetate

Name each of the following compounds: a. O N c. SO2 b. I Cl d. P2S5

Write the formula for each of the following compounds: a. diboron trioxide c. dinitrogen monoxide b. arsenic pentafluoride d. sulfur hexachloride

Name each of the following compounds: a. CuI f. S4N4 b. CuI2 g. SeCl4 c. CoI2 h. NaOCl d. Na2CO3 i. BaCrO4 e. NaHCO3 j. NH4NO3

Name each of the following compounds. Assume the acids are dissolved in water. a. HC2H3O2 g. H2SO4 b. NH4NO2 h. Sr3N2 c. Co2S3 i. Al2(SO3)3 d. ICl j. SnO2 e. Pb3(PO4)2 k. Na2CrO4 f. KClO3 l. HClO

Elements in the same family often form oxyanions of the same general formula. The anions are named in a similar fashion. What are the names of the oxyanions of selenium and tellurium: SeO4 22, SeO3 22, TeO4 22, TeO3 22?

Knowing the names of similar chlorine oxyanions and acids, deduce the names of the following: IO2, IO2 2, IO3 2, IO4 2, HIO, HIO2, HIO3, HIO4.

Write the formula for each of the following compounds: a. sulfur difluoride b. sulfur hexafluoride c. sodium dihydrogen phosphate d. lithium nitride e. chromium(III) carbonate f. tin(II) fluoride g. ammonium acetate h. ammonium hydrogen sulfate i. cobalt(III) nitrate j. mercury(I) chloride k. potassium chlorate l. sodium hydride

Write the formula for each of the following compounds: a. chromium(VI) oxide b. disulfur dichloride c. nickel(II) fluoride d. potassium hydrogen phosphate e. aluminum nitride f. ammonia g. manganese(IV) sulfide h. sodium dichromate i. ammonium sulfite j. carbon tetraiodide

Write the formula for each of the following compounds: a. sodium oxide h. copper(I) chloride b. sodium peroxide i. gallium arsenide c. potassium cyanide j. cadmium selenide d. copper(II) nitrate k. zinc sulfide e. selenium tetrabromide l. nitrous acid f. iodous acid m. diphosphorus pentoxide g. lead(IV) sulfide

Write the formula for each of the following compounds: a. ammonium hydrogen phosphate b. mercury(I) sulfide c. silicon dioxide d. sodium sulfite e. aluminum hydrogen sulfate f. nitrogen trichloride g. hydrobromic acid h. bromous acid i. perbromic acid j. potassium hydrogen sulfide k. calcium iodide l. cesium perchlorate

Name the acids illustrated below. a. b. c. d. e. Cl O N H P S C

Each of the following compounds is incorrectly named. What is wrong with each name, and what is the correct name for each compound? a. FeCl3, iron chloride b. NO2, nitrogen(IV) oxide c. CaO, calcium(II) monoxide d. Al2S3, dialuminum trisulfide e. Mg(C2H3O2)2, manganese diacetate f. FePO4, iron(II) phosphide g. P2S5, phosphorus sulfide h. Na2O2, sodium oxide i. HNO3, nitrate acid j. H2S, sulfuric acid

Chlorine has two natural isotopes: 37 17Cl and 35 17Cl. Hydrogen reacts with chlorine to form the compound HCl. Would a given amount of hydrogen react with different masses of the two chlorine isotopes? Does this conflict with the law of definite proportion? Why or why not?

What are the symbols for the following nonmetal elements that are most often present in compounds studied in organic chemistry: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur? Predict a stable isotope for each of these elements

Four Fe21 ions are key components of hemoglobin, the protein that transports oxygen in the blood. Assuming that these ions are 53Fe21, how many protons and neutrons are present in each nucleus, and how many electrons are present in each ion?

Which of the following statements is(are) true? For the false statements, correct them. a. All particles in the nucleus of an atom are charged. b. The atom is best described as a uniform sphere of matter in which electrons are embedded. c. The mass of the nucleus is only a very small fraction of the mass of the entire atom. d. The volume of the nucleus is only a very small fraction of the total volume of the atom. e. The number of neutrons in a neutral atom must equal the number of electrons.

The isotope of an unknown element, X, has a mass number of 79. The most stable ion of the isotope has 36 electrons and forms a binary compound with sodium having a formula of Na2X. Which of the following statements is(are) true? For the false statements, correct them. a. The binary compound formed between X and fluorine will be a covalent compound. b. The isotope of X contains 38 protons. c. The isotope of X contains 41 neutrons. d. The identity of X is strontium, Sr

For each of the following ions, indicate the total number of protons and electrons in the ion. For the positive ions in the list, predict the formula of the simplest compound formed between each positive ion and the oxide ion. Name the compounds. For the negative ions in the list, predict the formula of the simplest compound formed between each negative ion and the aluminum ion. Name the compounds. a. Fe21 e. S22 b. Fe31 f. P32 c. Ba21 g. Br2 d. Cs1 h. N32

The formulas and common names for several substances are given below. Give the systematic names for these substances. a. sugar of lead Pb(C2H3O2)2 b. blue vitrol CuSO4 c. quicklime CaO d. Epsom salts MgSO4 e. milk of magnesia Mg(OH)2 f. gypsum CaSO4 g. laughing gas N2O

Identify each of the following elements: a. a member of the same family as oxygen whose most stable ion contains 54 electrons b. a member of the alkali metal family whose most stable ion contains 36 electrons c. a noble gas with 18 protons in the nucleus d. a halogen with 85 protons and 85 electrons

An elements most stable ion forms an ionic compound with bromine, having the formula XBr2. If the ion of element X has a mass number of 230 and has 86 electrons, what is the identity of the element, and how many neutrons does it have?

A certain element has only two naturally occurring isotopes: one with 18 neutrons and the other with 20 neutrons. The element forms 12 charged ions when in ionic compounds. Predict the identity of the element. What number of electrons does the 12 charged ion ha

The designations 1A through 8A used for certain families of the periodic table are helpful for predicting the charges on ions in binary ionic compounds. In these compounds, the metals generally take on a positive charge equal to the family number, while the nonmetals take on a negative charge equal to the family number minus eight. Thus the compound between sodium and chlorine contains Na1 ions and Cl2 ions and has the formula NaCl. Predict the formula and the name of the binary compound formed from the following pairs of elements. a. Ca and N e. Ba and I b. K and O f. Al and Se c. Rb and F g. Cs and P d. Mg and S h. In and Br

By analogy with phosphorus compounds, name the following: Na3AsO4, H3AsO4, Mg3(SbO4)2

Identify each of the following elements. Give the number of protons and neutrons in each nucleus. a. 31 15X c. 39 19X b. 127 53X d. 173 70X

In a reaction, 34.0 g of chromium(III) oxide reacts with 12.1 g of aluminum to produce chromium and aluminum oxide. If 23.3 g of chromium is produced, what mass of aluminum oxide is produced?

Complete the following table. Atom/Ion Protons Neutrons Electrons 120 50Sn 25 12Mg21 56 26Fe21 79 34Se 35 17Cl 63 29Cu

Which of the following is(are) correct? a. 40Ca21 contains 20 protons and 18 electrons. b. Rutherford created the cathode-ray tube and was the founder of the charge-to-mass ratio of an electron. c. An electron is heavier than a proton. d. The nucleus contains protons, neutrons, and electrons.

What are the formulas of the compounds that correspond to the names given in the following table? Compound Name Formula Carbon tetrabromide Cobalt(II) phosphate Magnesium chloride Nickel(II) acetate Calcium nitrate

What are the names of the compounds that correspond to the formulas given in the following table? Formula Compound Name Co(NO2)2 AsF5 LiCN K2SO3 Li3N PbCrO4

Complete the following table to predict whether the given atom will gain or lose electrons in forming the ion most likely to form when in ionic compounds. Atom Gain (G) or Lose (L) Electrons Ion Formed K Cs Br S Se

Which of the following statements is(are) correct? a. The symbols for the elements magnesium, aluminum, and xenon are Mn, Al, and Xe, respectively. b. The elements P, As, and Bi are in the same family on the periodic table. c. All of the following elements are expected to gain electrons to form ions in ionic compounds: Ga, Se, and Br. d. The elements Co, Ni, and Hg are all transition elements. e. The correct name for TiO2 is titanium dioxide.

The elements in one of the groups in the periodic table are often called the coinage metals. Identify the elements in this group based on your own experience

Reaction of 2.0 L of hydrogen gas with 1.0 L of oxygen gas yields 2.0 L of water vapor. All gases are at the same temperature and pressure. Show how these data support the idea that oxygen gas is a diatomic molecule. Must we consider hydrogen to be a diatomic molecule to explain these results?

A combustion reaction involves the reaction of a substance with oxygen gas. The complete combustion of any hydrocarbon (binary compound of carbon and hydrogen) produces carbon dioxide and water as the only products. Octane is a hydrocarbon that is found in gasoline. Complete combustion of octane produces 8 L of carbon dioxide for every 9 L of water vapor (both measured at the same temperature and pressure). What is the ratio of carbon atoms to hydrogen atoms in a molecule of octane?

A chemistry instructor makes the following claim: Consider that if the nucleus were the size of a grape, the electrons would be about 1 mile away on average. Is this claim reasonably accurate? Provide mathematical support.

The early alchemists used to do an experiment in which water was boiled for several days in a sealed glass container. Eventually, some solid residue would appear in the bottom of the flask, which was interpreted to mean that some of the water in the flask had been converted into earth. When Lavoisier repeated this experiment, he found that the water weighed the same before and after heating, and the mass of the flask plus the solid residue equaled the original mass of the flask. Were the alchemists correct? Explain what really happened. (This experiment is described in the article by A. F. Scott in Scientific American, January 1984.)

Consider the chemical reaction as depicted below. Label as much as you can using the terms atom, molecule, element, compound, ionic, gas, and solid.

Each of the following statements is true, but Dalton might have had trouble explaining some of them with his atomic theory. Give explanations for the following statements. a. The space-filling models for ethyl alcohol and dimethyl ether are shown below. C O H These two compounds have the same composition by mass (52% carbon, 13% hydrogen, and 35% oxygen), yet the two have different melting points, boiling points, and solubilities in water. b. Burning wood leaves an ash that is only a small fraction of the mass of the original wood. c. Atoms can be broken down into smaller particles. d. One sample of lithium hydride is 87.4% lithium by mass, while another sample of lithium hydride is 74.9% lithium by mass. However, the two samples have the same chemical properties.

You have two distinct gaseous compounds made from element X and element Y. The mass percents are as follows: Compound I: 30.43% X, 69.57% Y Compound II: 63.64% X, 36.36% Y In their natural standard states, element X and element Y exist as gases. (Monatomic? Diatomic? Triatomic? That is for you to determine.) When you react gas X with gas Y to make the products, you get the following data (all at the same pressure and temperature): 1 volume gas X 1 2 volumes gas Y 88n 2 volumes compound I 2 volumes gas X 1 1 volume gas Y 88n 2 volumes compound II Assume the simplest possible formulas for reactants and products in the chemical equations above. Then, determine the relative atomic masses of element X and element Y

A single molecule has a mass of 7.31 3 10223 g. Provide an example of a real molecule that can have this mass. Assume the elements that make up the molecule are made of light isotopes where the number of protons equals the number of neutrons in the nucleus of each element.

Elements in Compound Masses of Elements 1. X and Y X 5 0.4 g, Y 5 4.2 g 2. Y and Z Y 5 1.4 g, Z 5 1.0 g 3. X and Y X 5 2.0 g, Y 5 7.0 g a. What are the assumptions needed to solve this problem? b. What are the relative masses of X, Y, and Z? c. What are the chemical formulas of the three compounds? d. If you decompose 21 g of compound XY, how much of each element is present?

What is the systematic name of Ta2O5? If the charge on the metal remained constant and then sulfur was substituted for oxygen, how would the formula change? What is the difference in the total number of protons between Ta2O5 and its sulfur analog?

A binary ionic compound is known to contain a cation with 51 protons and 48 electrons. The anion contains one-third the number of protons as the cation. The number of electrons in the anion is equal to the number of protons plus 1. What is the formula of this compound? What is the name of this compound?

Using the information in Table 2.1, answer the following questions. In an ion with an unknown charge, the total mass of all the electrons was determined to be 2.55 3 10226 g, while the total mass of its protons was 5.34 3 10223 g. What is the identity and charge of this ion? What is the symbol and mass number of a neutral atom whose total mass of its electrons is 3.92 3 10226 g, while its neutrons have a mass of 9.35 3 10223 g?

You have gone back in time and are working with Dalton on a table of relative masses. Following are his data. 0.602 g gas A reacts with 0.295 g gas B 0.172 g gas B reacts with 0.401 g gas C 0.320 g gas A reacts with 0.374 g gas C a. Assuming simplest formulas (AB, BC, and AC), construct a table of relative masses for Dalton. b. Knowing some history of chemistry, you tell Dalton that if he determines the volumes of the gases reacted at constant temperature and pressure, he need not assume simplest formulas. You collect the following data: 6 volumes gas A 1 1 volume gas B 4 volumes product 1 volume gas B 1 4 volumes gas C 4 volumes product 3 volumes gas A 1 2 volumes gas C 6 volumes product Write the simplest balanced equations, and find the actual relative masses of the elements. Explain your reasoning.