Year 9 Chemical Science Vocabulary

A complete list of vocabulary flashcards based on the Year 9 Chemical Science memorisation notes.

Atom

The smallest particle of an element that retains the properties of that element.

Element

A pure substance made from only one type of atom.

Atomic number (Z)

The number of protons in an atom’s nucleus.

Mass number (A)

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

Isotope

Atoms of the same element with the same number of protons but different numbers of neutrons.

Valence electrons

Electrons in the outermost occupied electron shell.

Group

A vertical column of the periodic table.

Period

A horizontal row of the periodic table.

Ion

A charged particle formed when an atom gains or loses electrons.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Ionic bond

The attraction between oppositely charged ions.

Ionic compound

A neutral compound containing positive and negative ions.

Covalent bond

A bond formed when atoms share a pair of electrons.

Covalent molecule

A group of non-metal atoms joined by shared electrons.

Diatomic molecule

A molecule containing two atoms.

Soluble

Able to dissolve in a solvent such as water.

Insoluble

Unable, or only able to dissolve to a very small extent, in a solvent.

Reactants

The starting substances in a chemical reaction.

Products

The new substances formed during a chemical reaction.

Word equation

A chemical reaction represented using substance names.

Chemical equation

A chemical reaction represented using chemical formulas.

Subscript

A small number in a chemical formula showing the number of atoms of the element immediately before it.

Coefficient

A number placed before a chemical formula that multiplies the entire formula.

Controlled variable

A factor kept the same during an investigation to make the comparison fair.

Validity

Whether an investigation measures what it is intended to measure.

Proton

A subatomic particle found in the nucleus with a charge of $+1$ and relative mass $1$.

Neutron

A subatomic particle found in the nucleus with a charge of $0$ and relative mass $1$.

Electron

A subatomic particle found in electron shells around the nucleus with a charge of $-1$ and almost no relative mass.

Alkali metals

The name given to Group $1$ elements.

Alkaline earth metals

The name given to Group $2$ elements.

Halogens

The name given to Group $17$ elements.

Noble gases

The name given to Group $18$ elements.

Law of conservation of mass

States that mass is neither created nor destroyed during a chemical reaction.