Back
Problem 27d
How many protons, neutrons, and electrons are in the following atoms? (d) 80Br
Problem 27e,f
How many protons, neutrons, and electrons are in the following atoms? (e) 184W (f) 181Ta.
- Each of the following isotopes is used in medicine. Indicate the number of protons and neutrons in each isotope: (a) samarium-153 (b) lutetium-177 (c) bismuth-213 (d) molybdenum-99 (e) lead-212 (f) caesium-131.
Problem 28
Problem 29a,b
Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol 79Br
Protons 25 82
Neutrons 30 64
Electrons 48 86
Mass no. 222 207
Complete the first row of the table excluding the isotope symbol.
Complete the second row of the table excluding the row with isotope symbol.
Problem 29c
Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol 79Br
Protons 25 82
Neutrons 30 64
Electrons 48 86
Mass no. 222 207
Complete the third row of the table.
Problem 29d
Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol 79Br
Protons 25 82
Neutrons 30 64
Electrons 48 86
Mass no. 222 207
Complete the fourth row of the table.
Problem 29e
Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol 79Br
Protons 25 82
Neutrons 30 64
Electrons 48 86
Mass no. 222 207
Complete the fifth row of the table.
Problem 30a
Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol 112Cd
Protons 38 92
Neutrons 58 49
Electrons 38 36
Mass no. 81 235
Complete the first row of the table.
Problem 30b
Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol 112Cd
Protons 38 92
Neutrons 58 49
Electrons 38 36
Mass no. 81 235
Complete the second row of the table.
Problem 30c,d
Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol 112Cd
Protons 38 92
Neutrons 58 49
Electrons 38 36
Mass no. 81 235
Complete the third row of the table.
Complete the fourth row of the table.
Problem 31a
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
Problem 31b,c
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: (b) the isotope of krypton with mass number 84 (c) the isotope of rhenium with mass number 187
Problem 31d
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: (d) the isotope of magnesium that has an equal number of protons and neutrons.
Problem 33
The atomic weight of boron is reported as 10.81, yet no atom of boron has the mass of 10.81 amu. Which is the best explanation?
a. The measurement of atomic mass is only reliable to two significant figures.
b. The atomic weight is an average of many individual atoms.
c. The atomic weight is an average of many isotopes of the same nuclear composition.
Problem 34b
(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 35
Only two isotopes of copper occur naturally: 63Cu (atomic mass = 62.9296 amu; abundance 69.17%) 65Cu (atomic mass = 64.9278 amu; abundance 30.83%). Calculate the atomic weight (average atomic mass) of copper.
Problem 36
Rubidium has two naturally occurring isotopes, rubidium-85 (atomic mass = 84.9118 amu; abundance = 72.15%) and rubidium-87 (atomic mass = 86.9092 amu; abundance = 27.85%). Calculate the atomic weight of rubidium
Problem 37a
(a) Thomson's cathode-ray tube (Figure 2.4) and the mass spectrometer (Figure 2.11) both involve the use of electric or magnetic fields to deflect charged particles. What are the charged particles involved in each of these experiments?
Problem 38a
Consider the mass spectrometer shown in Figure 2.11. Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (a) The paths of neutral (uncharged) atoms are not affected by the magnet.
Problem 38b
Consider the mass spectrometer shown in Figure 2.11. Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (b) The height of each peak in the mass spectrum is inversely proportional to the mass of that isotope.
Problem 40a
Massspectrometry is more often applied to molecules than to atoms. We will see in Chapter 3 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; abundance 0.0115%). (a) How many peaks will the mass spectrum have?
Problem 40c
Massspectrometry is more often applied to molecules than to atoms. We will see in Chapter 3 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; abundance 0.0115%). (c) Which peak will be the largest, and which the smallest?
Problem 41
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 nonmetal: (a) radon (b) tellurium (c) cadmium (d) chromium (e) barium (f) selenium (g) arsenic.
Problem 43
For each of the following elements, write its chemical symbol, determine the name of the group to which it belongs (Table 2.3), and indicate whether it is a metal, metalloid, or nonmetal: (a) polonium (b) strontium (c) neon (d) rubidium (e) sulfur.
- The elements of Group 14 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 44
Problem 45b
The structural formulas of the compounds n-butane and isobutane are shown below. (b) Determine the empirical formula of each.
Problem 45c
The structural formulas of the compounds n-butane and isobutane are shown below. (c) Which formulas—empirical, molecular, or structural—allow you determine these are different compounds?
Problem 46a
Ball-and-stick representations of benzene, a colorless liquid often used in organic chemistry reactions, and acetylene, a gas used as a fuel for high-temperature welding, are shown below. (a) Determine the molecular formula of each.
Problem 47a
What are the molecular and empirical formulas for each of the following compounds? Write the molecular formula for the following compound.
Problem 48
Two substances have the same molecular and empirical formulas. Does this mean that they must be the same compound?