A hydrogen-filled balloon was ignited and 1.50 g of hydrogen reacted with 12.0 g of oxygen. How many grams of water vapor formed? (Assume that water vapor is the only product.)

Solution : Here, we need to fill the blanks of the table using the other data given in the table. An atom is the smallest particle of an element. Any atom of an element is made up of three subatomic pa rticles namely rotons, neutrons nd lectrons. These subatomic particles gives the element's atomic number and mass number. Protons a re p ositively charged particle, electrons gatively charged and neutrons a re neutral, which means there isno charge. In neutral state, an atom has qual number of protons and electrons. An atom’s atomic number gives number of protons a nd electrons. the sum of number of protons and neutrons gives the mass number of an atom. the difference of mass number and number of protons gives number of neutrons. Let’s consider a carbon(C) atom, to show the representation of atomic number and mass number. The following is the representation of atomic number and mass number of an element. Let’s consider all the atoms are in neutral state. Let’s consider the 1st set of data in the table, the symbol of the element is given as Br. We have to find the remaining data : Br is the chemical symbol of Bromine. The m ass number is obtained from the symbol given Br, it is : 7 9 From, the periodic table, we know atomic number of Br is 35. Atomic number gives the number of protons a nd electrons. Number of neutrons = mass number - number of protons Hence, Number of protons = 35 Number of electrons = 35. Number of neutrons = 79 - 35 = 44. Now let’s consider the second set of data : Number of protons and neutrons i s given. Number of p rotons = 25. Number of neutrons = 30. Number of protons gives atomic number. Hence, atomic number = 25. Sum of number of p rotons and eutrons gives mass number. Hence, mass number = 25+30 = 55. Number of electrons = number of protons. Hence, Number of electrons = 25. 25 is the atomic number of Manganese(Mn). In the third set of data : Number of electrons and neutrons is given. Number of neutrons = 64. Number of electrons = 48. Number of electrons = number of protons. Hence, Number of p rotons= 48. Number of protons gives atomic number. Hence, a tomic number = 48. Sum of number of p rotons and neutrons gives mass number. Hence, mass number = 48+64 =112. 48 is the atomic number of Cadmium(Cd). In the fourth set of data : Number of electrons and mass number is given. Number of electrons = 86. Mass number = 222. Number of electrons = number of protons. Hence, Number of p rotons 86. Number of protons gives atomic number. Hence, atomic number = 86. Number of neutrons = Mass number -Number of protons = 222-86 = 136. 86 is the atomic number of adon(Rn). In the fifth set of data : Number of protons a nd ass number is given. Number of p rotons= 82. Mass number = 207. Number of electrons = number of protons. Hence, Number of e lectrons = 82. Number of protons gives atomic number. Hence, a tomic number = 82. Number of neutrons = Mass number -Number of protons = 207-82 = 125. 82 is the atomic number of Lead(Pb). Based on the above derivations, the table is as follows: 79 55 112 222 207 Symbol Br Mn Cd Rn Pb Protons 35 25 48 86 82 Neutrons 44 30 64 136 125 Electrons 35 25 48 86 82 Mass 79 55 112 222 207 number