(40) GCSE Chemistry Revision "Relative Formula Mass"

Relative Formula Mass

The sum of the relative atomic masses of the atoms in the numbers shown in the formula.

Abundance

How common an isotope is.

Isotope

Variants of a chemical element that have the same number of protons but different numbers of neutrons.

Atomic Number

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

Mass Number

The total number of protons and neutrons in an atomic nucleus.

Relative Atomic Mass

The average mass of the isotopes of an element, weighted by their abundance.

Chlorine-35

An isotope of chlorine with a mass number of 35, having 17 protons and 18 neutrons.

Chlorine-37

An isotope of chlorine with a mass number of 37, having 17 protons and 20 neutrons.

Formula of Methane

CH₄, consisting of one carbon atom and four hydrogen atoms.

Units of Relative Formula Mass

Relative formula mass has no units.

Calculation of Relative Formula Mass

Involves adding the relative atomic masses based on the number of each type of atom in the formula.

Calcium Sulfate

A compound with a relative formula mass calculated as the sum of one calcium (40), one sulfur (32), and four oxygen (16) atoms, totaling 136.

Magnesium Hydroxide

A compound with a relative formula mass calculated as the sum of one magnesium (24), two oxygen (16), and two hydrogen (1) atoms, totaling 58.