(40) GCSE Chemistry Revision "Atomic Number and Mass Number"

Atomic Number

The number of protons in the nucleus of an atom, which determines the element's identity.

Mass Number

The total number of protons and neutrons in an atom's nucleus.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Neutral particles found in the nucleus of an atom that do not have a charge.

Electrons

Negatively charged particles that orbit the nucleus of an atom.

Isotopes

Atoms of the same element with different numbers of neutrons.

Positive Ion

An atom that has lost one or more electrons, resulting in a net positive charge.

Negative Ion

An atom that has gained one or more electrons, resulting in a net negative charge.

Lithium (Li)

An element with an atomic number of 3 and a mass number of 7.

Boron (B)

An element with 4 protons, 5 neutrons, and 4 electrons.

Chlorine (Cl) Isotopes

Chlorine has isotopes with 17 protons and varying neutrons (18 and 20 for its common isotopes).