Question

unit 2 test - atomic structure and radioactivity (fall 2026)
multiple choice
identify the choice that best completes the statement or answers the question. you must bubble your answer
on your bubble sheet for full credit. no credit can be given for mis-bubbled answers. double check
your bubbles!

1. which statement does not describe fission?

a. it is the fuel source of stars.
b. a neutron starts the process.
c. a very heavy nucleus splits into smaller nuclei.
d. the chain reaction needs to be controlled.

1. an atom has 8 protons and 8 neutrons. its name in hyphen notation is

a. oxygen-16
c. sulfur-32
b. sulfur-16
d. oxygen-8

1. an aluminum isotope consists of 13 protons, 13 electrons, and 14 neutrons. its mass number is

a. 13.
c. 40.
b. 14.
d. 27.

1. what does the band of stability for atomic nuclei refer to?

a. the ratio of # protons to # neutrons
b. the ratio of atomic mass units to carbon-12
c. the ratio of # neutrons to # protons
d. the half-life of decay particles

1. what does the 90 in ( _{90}^{231} )th represent?

a the atomic number
c. the number of neutrons
b. the nuclide number
d. the mass number

1. which statement applies to nuclear fusion?

a. it occurs at low temperatures.
b. it takes place in the sun.
c. it produces radioactive waste.
d. its used for atomic bombs.

1. a reaction in which small mass nuclei combine to form one larger mass nucleus is a _.

a. chemical reaction
b. fission reaction
c. fusion reaction
d. background reaction

1. what is the minimum number of neutron to proton ratio you can have for a nucleis stability?

a. 82:1
c. 1:1
b. 1.5:1
d. 1:56

Explanation:

1.

Fusion is the fuel source of stars, not fission. Fission is when a heavy nucleus splits, a neutron starts the process, and chain reactions need control.

Atomic number (protons) = 8 is oxygen. Hyphen notation is element - mass number (protons + neutrons = 8 + 8 = 16).

Mass number = protons + neutrons = 13 + 14 = 27.

Answer:

a. It is the fuel source of stars.

2.