Nucleotide Symbols: Atomic Number, Mass Number, Ions, and Isotopes

Proton

A positively charged particle found in the nucleus of an atom that determines the element's identity.

Atomic Number

The number of protons in the nucleus of an atom, which identifies the element.

Mass Number

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

Isotope

Atoms of the same element that have different numbers of neutrons and therefore different mass numbers.

Nuclide Symbol

A notation that represents an atom, consisting of the element symbol, the atomic number, and the mass number.

Ion

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

Average Atomic Mass

The weighted average of the masses of an element's isotopes based on their natural abundance.

Chlorine-35

An isotope of chlorine with 17 protons and 18 neutrons.

Chlorine-37

An isotope of chlorine with 17 protons and 20 neutrons.

Neutral Atom

An atom with an equal number of protons and electrons, resulting in no overall charge.

Charge of an Ion

The net electric charge of an ion, resulting from the difference in the number of protons and electrons.

Atomic Mass Unit

A unit of mass used to express atomic and molecular weights, approximately equal to the mass of one proton or neutron.

Relative Abundance

The proportion of a particular isotope present in a sample of an element.

Fractional Atomic Mass

The average atomic mass of an element that can include decimal values due to the presence of isotopes.