Ch. 2 Atoms and Bonds

The atomic number of an atom is determined by the number of

• protons

• neutrons

• electrons

• valence electrons

The vertical columns on the periodic table organize elements by

• periods

• metals

• nonmetals

• families

When an atom loses an electron, it

• becomes a negative ion

• becomes a positive ion

• forms a covalent bond

• gains protons

Which of these is a property of an ionic compound?

• low melting point

• poor conductor of electricity

• crystal shape

• shared electrons

A chemical bond in which a pair of electrons is shared between two atoms is called

• covalent

• ionic

• polyatomic

• triple

True or False:

Using the periodic table, you can determine that a potassium atom has one valence electron.

• True

• False

True or False:

When a chlorine atom gains an electron, it becomes a positive ion.

• True

• False

True or False:

When atoms share electrons unequally, a polar bond forms.

• True

• False

True or False:

Two polar molecules have weaker attractions between them than two nonpolar molecules do.

• True

• False

True or False:

Hardness is determined by how easily a mineral can be scratched.

• True

• False