Chapter 2 - The Chemical Level of Organization

Question 1

1. Define atom.

Answer 1

An atom is the smallest stable unit of matter.

Question 2

2. Atoms of the same element that have different numbers of neutrons are called _____.

Answer 2

Atoms of the same element that have the same atomic number but different numbers of neutrons are called isotopes.

Question 3

3. How is it possible for two samples of molecular hydrogen to contain the same number of atoms, yet have different molecular weights?

Answer 3

Hydrogen has three isotopes: hydrogen-1, with a mass number of 1; deuterium with a mass number of 2; and tritium, with a mass number of 3. The heavier sample must contain a higher proportion of one or both of the heavier isotopes.