Advanced Biology Ch 2 Basic Chemistry Varner

An element is a pure substance that cannot be broken down into other substances by physical or chemical means.

• True

• False

An ionic bond is formed when two atoms share electrons.

• True

• False

If a neutral atom contains 18 protons, it also contains 18 electrons.

• True

• False

As the H+ concentration of a solution in water increases, the OH– concentration decreases.

• True

• False

Water has a low heat of vaporization and do not require much energy to break the hydrogen bonds.

• True

• False

Water is cohesive and adhesive.

• True

• False

Frozen water is less dense than liquid water.

• True

• False

Acidic solutions have a higher concentration of hydroxide ions than hydrogen/hydronium ions.

• True

• False

Which of these represents a formula for a chemical compound?

• H₂

• C

• P

• H₂O

An atom of fluorine has nine electrons. Its second energy level has ____.

• 2 electrons

• 8 electrons

• 7 electrons

• 9 electrons