science, chemisty

A proton has a relative charge of +1

A proton has a relative mass of 1

A neutron has a relative mass of 1

A neutron has a relative charge of 0

A electron has a relative mass of 0.0005

A electron has a relative charge of -1

The number on the top right hand side of the symbol (23) is the atomic number.

The number on the bottom left hand side (11) is the mass number

The symbol for sodium is Na.

Isotopes are different forms of the same element.

Isotopes have the same number of protons but different number of neutrons.

Isotopes have the same atomic number but different mass numbers.