What is formed when two or more atoms form a chemical bond?

• Element

• Molecule

• Compound

• Ion

If atoms of different elements combine, the molecule is called a ________.

• compound

• isotope

• mixture

• element

For example, 2 atoms of H and 1 atom of O can bind to form a molecule of water, H2O; since it contains different types of atoms, it is classified as a ________.

A molecular formula represents the numbers and types of atoms in a ________.

• molecule

• compound

• mixture

• element

How many hydrogen atoms are present in a molecule of glucose (C6H12O6)?

• 12

• 6

• 24

• 18

Water (H2O) contains how many oxygen atoms?

• 1

• 2

• 3

• 0

Structural formulas can be used to illustrate how atoms are joined and arranged in molecules.

• True

• False

Each atom forms a specific number of covalent bonds, based on the number of electrons it contains in its outermost shell. H atoms form single bonds.

• True

• False

What do three-dimensional molecular models show?

• Spatial relationships between atoms

• The melting point of a substance

• The color of a compound

• The boiling point of a substance

What is the molecular formula for the molecule with the structural formula H—O—H?

• H2O

• H2O2

• HO2

• H3O