CHAPTER 3

Question 1

It depends on the number of electrons, protons, and neutrons it contains.

Answer 1

mass of an atom

Question 2

The mass of the atom in atomic mass units (amu).

Answer 2

atomic mass or atomic weight

Question 3

A mass exactly one-twelfth the mass of one carbon-12 atom

Answer 3

1 AMU or one atomic mass unit

Question 4

The carbon isotope that has six protons and six neutrons.

Answer 4

carbon-12

Question 5

When we measure atomic mass of an element, we must generally settle for the ____ mass of naturally occurring mixture of isotopes.

Answer 5

average

Question 6

The amount of a substance that contains as many elementary entities (atoms, molecules, or other particles) as there are atoms in exactly 12 g
(or 0.012 kg) of the carbon-12 isotope.

Answer 6

mole (mol)

Question 7

The actual number of atoms in 12 g or carbon-12 is determined experimentally.

Answer 7

Avogadro’s number

NA = 6.0221413 X 10^23