Use carbon-12, the most common isotope of carbon, to define these terms: atomic number, mass number, valence. Which of these numbers is most related to the chemical behavior of an atom? Explain.

A proton ___________:

a) Has one positive charge.

b) Has one AMU.

c) Is found in the nucleus of the atom.

d) Only a and b are true.

e) a, b, and c are true.

The average oxygen atom has a mass number of 16 and an atomic number of 8. This means that the number of neutrons in this oxygen atom is:

a) 24.

b) 8.

c) 16.

d) 4.

e) 2.

How many valence electrons does an atom with five total electrons have?

a) 5.

b) 7.

c) 3.

d) 2.

e) 1.