Year 9 Chemistry - Key Topics Vocabulary

Vocabulary practice cards covering Year 9 Chemistry concepts, including atomic structure, electron arrangement, ions, ionic formulas, radioactivity, and half-life.

Isotopes

Atoms of the same element that have the same number of protons but a different number of neutrons, resulting in a different mass number.

Carbon-12

An isotope of carbon containing $6$ protons and $6$ neutrons.

Carbon-14

An isotope of carbon containing $6$ protons and $8$ neutrons.

Flame test light release

The process where energy is absorbed, causing an electron to move to a higher energy shell, and then released as visible light when the electron falls back down to a lower energy shell.

Electron configuration

The arrangement of electrons in energy shells around the nucleus, with maximum capacities of $2$ in the 1st shell, $8$ in the 2nd shell, and $8$ in the 3rd shell.

Period

A row on the Periodic Table that corresponds to the total number of electron shells in an atom.

Group

A column on the Periodic Table that is related to the number of electrons in an atom's outer shell and how it reacts.

Ion

An atom that has gained or lost electrons, giving it an overall charge.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic compounds

Compounds formed when positive and negative ions attract each other to achieve an overall charge of zero.

Magnesium chloride formula

The chemical formula $\text{MgCl}_2$, formed by combining one $\text{Mg}^{2+}$ ion with two $\text{Cl}^{-}$ ions to balance the charges to zero.

Aluminium oxide formula

The chemical formula $\text{Al}_2\text{O}_3$, formed by combining two $\text{Al}^{3+}$ ions ($+6$ charge) and three $\text{O}^{2-}$ ions ($-6$ charge) to equal a net charge of zero.

Radioactivity

The process by which unstable atomic nuclei naturally release radiation to become more stable.

Radioisotope

An isotope with an unstable nucleus that undergoes radioactive decay.

Alpha (\alpha) radiation

Radiation made of a helium nucleus with a $+2$ charge, relatively large mass, and low penetrating power.

Beta (\beta) radiation

Radiation made of a fast-moving electron with a $-1$ charge, very small mass, and medium penetrating power.

Gamma (\gamma) radiation

Electromagnetic radiation with $0$ charge, no rest mass, and high penetrating power.

Half-life

The time it takes for half of a radioactive sample to decay.