Chem 1305 –Home-work 4
1)
NAME:
In the formula C4H8O2 ________.
A) there are 2 different elements
B) the ratio of carbon to hydrogen to oxygen atoms is 2:4:1
C) the percentage by mass of hydrogen is the same as oxygen
D) there is a total of 10 atoms
E) there are two elements with the same percentage by mass
2) In which of the following pairs of formulas do the two members of the pair contain the same number of
elements as well as the same number of atoms?
A) Co and CO
B) NaHCO3 and NaHSO4
D) K2SO4 and BaCl2
E) Cl2CO and C2HCl
C) SO3 and SO2
3) Atoms are neutral because ________.
A) All atoms contain neutrons
B) Neutrons neutralize the () and () charges in the atom
C) The atomic number equals the number of electrons
D) The number of subatomic particles in the nucleus is always an even number
E) Equal numbers of protons and neutrons
4) An atom contains 12 neutrons and 14 electrons. The mass number and the number of protons for this
atom are, respectively, ________.
A) 14 and 26
B) 40 and 14
C) 26 and 14
D) 26 and 12
E) the mass number cannot be determined and 14
40
5) Which of the following statements is correct for 19 K?
A) contains more protons than neutrons
B) contains more electrons than protons
C) contains an equal number of protons and neutrons
D) contains more neutrons than electrons
6) The total number of subatomic particles (protons, electrons, and neutrons) in an atom of 75Ge is
________.
A) 86
B) 84
C) 107
D) 143
E) 327
7) Mercury-202 has how many neutrons in its nucleus?
A) 22
B) 102
C) 122
D) 202
8) Three naturally occurring isotopes exist for the hypothetical element athenium. 2.50% of athenium
atoms have a relative mass of 26.0 amu, 75.0% of athenium atoms have a relative mass of 27.0 amu,
and 22.5% of athenium atoms have a relative mass of 28.0 amu. What is the atomic mass of
athenium?
A) 26.8 amu
B) 27.0 amu
C) 28.0 amu
D) 27.9 amu
E) 27.2 amu
9) Three naturally occurring isotopes of carbon exist: The atomic mass of carbon is 12.01 amu. Which of
the three carbon isotopes is most abundant in nature?
A) carbon-12
B) carbon-13
D) all three occur with equal abundance
C) carbon-14
E) insufficient information given to calculate
Place in the blank the letter of the correct response in each horizontal row of choices.
10) ________ Number of elements in the compound Al2SO4
A) 3
B) 4
C) 5
D) 7
11) ________ Number of atoms in the formula Ca(HCO3)2
A) 11
B) 15
C) 9
D) 10
C) 20
D) 16
32
12) ________ Number of neutrons in 16
S
A) 15
B) 17
20
13) ________ Number of electrons in 10
Ne
A) 20
B) 10
C) 30
D) 12
14) ________ Number of subatomic particles in 18
8 O
A) 26
B) 8
C) 18
D) 22
C) 14
D) 20
C) I
D) Re
15) ________ Number of protons in 14
7 C
A) 7
B) 8
16) ________ Identity of X in
A) Ti
186
X
75
B) Cr
17) ________ Mass number of a K isotope containing 21 neutrons
A) 19
B) 21
C) 40
D) 28
18) ________ Mass number of an isotope containing 45 protons and 58 neutrons
A) 13
B) 45
C) 58
D) 103
19) ________ An atom of Cu containing an equal number of protons, neutrons and electrons
A) 29
29 Cu
B) 58
29 Cu
C) 87
29 Cu
29
D) 58
X
23
20) ________ Nuclear charge of 11
Na
A) 10
B) 12
C) 11
D) 23