The central core of an atom is called the hub.

• true

• false

The number of protons in an atom is called the atomic mass.

• true

• false

The symbol for chlorine is C.

• true

• false

The identity of an element is determined by the number of protons.

• true

• false

The region around the nucleus occupied by the electrons is called the negative zone.

• true

• false

The maximum number of electrons in the second energy level of an atom is 4.

• true

• false

The sum of the number of protons and the number of neutrons in an atom is the mass number.

• true

• false

The nucleus of most atoms is composed of

• tightly packed protons.

• tightly packed neutrons

• tightly packed protons and neutrons.

• loosely connected protons and electrons

An aluminum isotope consists of 13 protons, 13 electrons, and 14 neutrons. Its mass number is

• 13

• 14

• 27

• 40

A subatomic particle that has a negative electric charge is a(n)

• proton

• neutron

• electron

• nucleus