Chapter 16 Compounds: Test A

Which statement best explains why atoms form chemical bonds with other atoms?

• Most atoms are less stable when they combine with other atoms.

• When atoms collide with other atoms, they bond automatically.

• Atoms are always attracted to other atoms.

• Most atoms are unstable unless they are combined with other atoms.

When an atom gains or loses electrons, it has an electrical charge. It is known as:

• an ion.

• a free radical.

• a hydrate.

• a monoatomic molecule.

Transferring or sharing electrons between atoms forms:

• mixtures.

• bonds.

• alloys.

• solutions.

Groups of atoms held together by covalent bonds are called:

• molecules.

• elements.

• mixtures.

• alloys.

Bonding between atoms produces an outermost energy level for each atom filled with:

• 1 electron

• 8 electrons

• 16 electrons

• 32 electrons

Sodium forms an ionic bond with chlorine when sodium ____ an electron and chlorine ____ an electron.

• shares, shares

• loses, gains

• gains, loses

• loses, loses

How many atoms of aluminum (Al), sulfur (S), and oxygen (O) are in each molecule of Al₂(SO₄)₃?

• 2-aluminum, 1-sulfur, 4-oxygen

• 1-aluminum, 3-sulfur, 4-oxygen

• 2-aluminum, 3-sulfur, 3-oxygen

• 2-aluminum, 3-sulfur, 12-oxygen

Ionic bonds form:

• between oppositely charged atoms.

• molecules.

• by sharing electrons.

• only between pairs of atoms.

The Mg atom becomes the ion, Mg²⁺, when it:

• gains 2 electrons.

• loses 2 electrons.

• gains 2 protons.

• loses 2 protons.

In the atom pictured, the small dark circles represent electrons. The number of valence electrons in the atom pictured is:

• 2

• 3

• 5

• 7