Name ________________________________________________________
Unit 2: The Atom
Date ________________________________
Multiple Choice Questions
1. The modern model of the atom shows electrons are
(1) orbiting the nucleus in fixed paths
(2) found in regions called orbitals
(3) combined with neutrons in the nucleus (4) located in a sphere covering the nucleus
2. Which conclusion was drawn from the results of the gold foil experiment?
(1) An atom is electrically neutral
(2) An atom is mostly empty space
(3) The nucleus of an atom is negatively charged
(4) The electrons in an atom are located in specific shells
3. Which subatomic particles are paired with their charges?
(1) electron – positive, neutron – negative, proton – neutral
(2) electron – negative, neutron – neutral, proton – positive
(3) electron – negative, neutron – positive, proton – neutral
(4) electron – neutral, neutron – positive, proton – negative
4. Compared to the charge of a proton, the charge of an electron has
(1) a greater magnitude and the same sign
(2) a greater magnitude and the opposite sign
(3) the same magnitude and the same sign
(4) the same magnitude and the opposite sign
5. Which phrase describes the charge and mass of a neutron?
(1) a charge of +1 and no mass (2) a charge of +1 and an approximate mass of 1 amu
(3) no charge and no mass
(4) no charge and an approximate mass of 1 amu
6. Which subatomic particles are found in the nucleus of an atom of beryllium?
(1) electrons and protons
(2) electrons and positrons
(3) neutrons and protons
(4) neutrons and electrons
7. Which particle has two neutrons?
(1)
(2)
(3)
8. The charge of a beryllium-9 nucleus is
(1) 0
(2) +9
(3) +2
(4)
(4) +4
9. An atom is electrically neutral because the
(1) number of protons equals the number of electrons
(2) number of protons equals the number of neutrons
(3) ratio of the number of neutrons to the number of electrons is 1:1
(4) ratio of the number of neutrons to the number of protons is 2:1
10. What is the number of electrons in a potassium atom?
(1) 18
(2) 19
(3) 20
(4) 39
11. Which principal energy level can hold a maximum number of 8 electrons?
(1) 1
(2) 2
(3) 3
(4) 4
12. The nuclides I-131 and I-133 are classified as
(1) isomers of the same element
(2) isomers of Xe-131 and Cs-133
(3) isotopes of the same element
(4) isotopes of Xe-131 and Cs-133
13. Which notations represent hydrogen isotopes?
(1)
(2)
(3)
(4)
14. Naturally occurring gallium is a mixture of isotopes that contain 60.11% of Ga-69
(atomic mass = 68.93 u) and 39.89% of Ga-71 (atomic mass = 70.92 u). Which numerical
setup can be used to determine the atomic mass of naturally occurring gallium?
(1) (68.93 u + 70.92 u)
(2) (68.93 u)(0.6011)
2
(70.92 u)(0.3989)
(3) (68.93 u)(0.6011) + (70.92 u)(0.3989)
(4) (68.93 u)(39.89) + (70.92 u)(60.11)
15. Which electron configuration represents an atom of aluminum in an excited state?
(1) 2-7-4
(2) 2-7-7
(3) 2-8-3
(4) 2-8-6
16. The atoms in a sample of an element are in excited states. A bright-line spectrum is
produced when these atoms
(1) absorb energy (2) absorb positrons (3) emit energy (4) emit positrons
17. In the ground state, an atom of which element has two valence electrons?
(1) Cr
(2) Cu
(3) Ni
(4) Se
18. Compared to a calcium atom, the calcium ion Ca+2 has
(1) more protons (2) fewer protons (3) more electrons (4) fewer electrons
19. What is the total number of electrons in a Cu+ ion?
(1) 28
(2) 29
(3) 30
(4) 36
20. What is the total number of electrons in a S-2 ion?
(1) 10
(2) 14
(3) 16
(4) 18
21. Which ion contains the same total number of electrons as Cl -?
(1) S-2
(2) Br(3) Mg+2
(4) Na+
22. Which ion has the same electron configuration as an atom of argon?
(1) Al+3
(2) O-2
(3) K+
(4) F-