Year 9 AQA Chemistry: Atomic Structure and Isotopes

Revision vocabulary flashcards covering atomic structure, subatomic particles, isotopes, historical atomic models, electronic configurations, and chemical reaction products.

Nucleus

The central part of the atom that contains protons and neutrons.

Electron

The subatomic particle with the lowest mass, located in shells orbiting the nucleus.

Mass Number

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

Proton

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

Neutron

A subatomic particle discovered by Chadwick, located in the nucleus with a relative mass of $1$ and a relative charge of $0$ (neutral).

Isotope

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

Relative Atomic Mass ($A_r$)

The average mass value of an element calculated using percentage abundance: $A_r = \frac{(\text{mass} \times \text{percentage})\text{ of isotope } 1 + (\text{mass} \times \text{percentage})\text{ of isotope } 2}{100}$.

Plum Pudding Model

An atomic model suggesting that the atom was a ball of positive charge with negative electrons embedded in it.

Alpha Particle Scattering Experiment

An experiment that disproved the plum pudding model by showing that most alpha particles passed straight through (the atom is mostly empty space) and some particles were deflected or reflected (the atom has a small, concentrated positive nucleus at the centre).

Niels Bohr

The scientist who adapted the nuclear model by proposing that electrons orbit the nucleus in specific shells (energy levels).

James Chadwick

The scientist whose experimental work proved the existence of neutrons, leading to a better understanding of isotopes.

Hydrogen Atom Structure

An atomic structure consisting of $1$ proton, $0$ neutrons, and $1$ electron.

Helium Atom Structure

An atomic structure consisting of $2$ protons, $2$ neutrons, and $2$ electrons.

Electronic Structure of Lithium

An electron configuration with $2$ electrons in the inner shell and $1$ electron in the outer shell, written as $2,1$.

Products of $\text{Pb(NO}_3)_2 + 2\text{KCl} \rightarrow 2\text{KNO}_3 + \text{PbCl}_2$

The chemical substances formed in the reaction: potassium nitrate ($\text{KNO}_3$) and lead chloride ($\text{PbCl}_2$).