3 The atomic mass of an element is the weighted average of the masses of (1) its two most abundant isotopes(3) all of its naturally occurring isotopes (2) its two least abundant isotopes(4) all of its radioactive isotopes
4 Which statement is true about the charges assigned to an electron and a proton? (1) Both an electron and a proton are positive.
(2) An electron is positive and a proton is negative.
(3) An electron is negative and a proton is positive.
(4) Both an electron and a proton are negative.
5 Which statement best explains why most atomic masses on the Periodic Table are decimal numbers? (1) Atomic masses are determined relative to an H–1 standard. (2) Atomic masses are determined relative to an O–16 standard. (3) Atomic masses are a weighted average of the naturally occurring isotopes. (4) Atomic masses are an estimated average of the artificially produced isotopes.
6 An electron has a charge of
(1) –1 and the same mass as a proton(3) –1 and a smaller mass than a proton (2) +1 and the same mass as a proton(4) +1 and a smaller mass than a proton
7 The atomic number of an atom is always equal to the number of its (1)
protons, only(3) protons plus neutrons
(2) neutrons, only(4) protons plus electrons
8 Which subatomic particle has no charge?
(1) proton (2) neutron(3) the nucleus(4)electron
9 The atomic mass of an element is calculated using the
(1) atomic number and the ratios of its naturally occurring isotopes (2) atomic number and the half-lives of each of its isotopes (3) masses and the ratios of its naturally occurring isotopes (4) masses and the half-lives of each of its isotopes
10 Which statement best describes electrons?
(1) They are positive subatomic particles and are found in the nucleus. (2) They are positive subatomic particles and are found surrounding the nucleus. (3) They are negative subatomic particles and are found in the nucleus. (4) They are negative subatomic particles and are found surrounding the nucleus.
11 An atom of carbon-12 and an atom of carbon-14 differ in
(1) atomic number(3) nuclear charge
(2) mass number(4) number of electrons
12 Subatomic particles can usually pass undeflected through an atom because the volume of an atom is composed of
(1) an uncharged nucleus(3) neutrons
(2) largely empty space(4) protons
13 What is the total number of protons in the nucleus of an atom of potassium-42? (1) 15(2) 19 (3) 39(4) 42
14 As a Ca atom changes to Ca2+ , the number of neutrons in its nucleus (1) decreases(2) increases(3) remains the same(4) doubles
15 All the isotopes of a given atom have
(1) the same mass number and the same atomic number
(2) the same mass number but different atomic numbers
(3) different mass numbers but the same atomic number
(4) different mass numbers and different atomic numbers
16 Which particles are found in the nucleus of an atom?
(1) electrons, only(3) protons and electrons
(2) neutrons, only(4) protons and neutrons
17 What is the total number of electrons found in an atom of sulfur? (1) 6(2) 8 (3) 16 (4) 32
18 The nucleus of an atom of cobalt-58 contains
(1) 27 protons and 31 neutrons(3) 59 protons and 60 neutrons (2) 27 protons and 32 neutrons(4) 60 protons and 60 neutrons
19 What is the total number of neutrons in an atom of an element that has a mass number of 19 and an atomic number of 9? (1) 9(2) 10 (3) 19(4) 28
20 The nucleus of an atom of K-42 contains
(1) 19 protons and 23 neutrons(3) 20 protons and 19 neutrons (2) 19 protons and 42 neutrons(4) 23 protons and 19 neutrons
21 The number of neutrons in the nucleus of an atom can be determined by (1) adding the atomic number to the mass number
(2) subtracting the atomic number from the mass number
(3) adding the mass number to the atomic mass
(4) subtracting the mass number from the atomic number
Part II Type Questions
In the modern model of the atom, each atom is composed of three major subatomic (or fundamental) particles.
22 Name the subatomic particles contained in the nucleus of the atom. 
Protons and Neutrons
23 State the charge associated with each type of subatomic particle contained in the nucleus of the atom.  Proton (+1)
24 What is the net charge of the nucleus? 
The net charge of the nucleus is a positive
Base your answers to questions 25 on the data table below, which shows three isotopes of neon.
25 In terms of atomic particles, state one difference between these three isotopes of neon.  They have different number of neutrons
26 Describe, in terms of subatomic particles found in the nucleus, one difference between the nuclei of carbon-12 atoms and the nuclei of carbon-13 atoms. The response must include both isotopes.  Carbon-13 has one more neutron than Carbon-12
27 In the early 1900s, experiments were conducted to determine the structure of the atom. One of these experiments involved bombarding gold foil with alpha particles. Most alpha particles passed directly through the foil. Some, however, were deflected at various angles. Based on this alpha particle experiment, state two conclusions that were made concerning the structure of an atom. 
Nucleus is small
Nucleus is positively charged