Yr9- C1: Atomic structure

Atom

The smallest part of an element that can exist.

Compound

A substance formed from two or more elements chemically combined in fixed proportions.

Element

A pure substance made up of one type of atom.

Mixture

Two or more elements or compounds mixed together but not chemically bonded.

Law of Conservation of Mass

The mass of the reactants in a chemical reaction is always equal to the mass of the products.

Filtration

A physical process used to separate insoluble solids from soluble substances.

Crystallisation

A process used to separate soluble solids from a solvent by evaporating the solvent.

Simple Distillation

A process used to separate a pure liquid from a mixture of liquids or a solid.

Paper Chromatography

A technique used to separate and identify substances in a mixture based on their different affinities for a solvent.

Rf Value

A value calculated in paper chromatography to compare the distance moved by a compound to the distance moved by the solvent.

Miscible

Liquids that are capable of mixing and dissolving in each other.

Fractional Distillation

A method used to separate miscible liquids or gases based on their difference in boiling points.

Democritus

Proposed the idea that matter is made up of indivisible particles called atoms.

John Dalton

Proposed the atomic theory, stating that all matter is made up of tiny, indivisible spheres called atoms.

JJ Thomson

Discovered the electron and proposed the plum pudding model of the atom.

Ernest Rutherford

Proposed the nuclear model of the atom, with a small, dense nucleus and orbiting electrons.

Niels Bohr

Proposed the idea of electron shells or energy levels around the nucleus.

James Chadwick

Discovered the neutron, a particle with no electrical charge found in the nucleus of an atom.

Proton

A subatomic particle with a positive charge found in the nucleus of an atom.

Electron

A subatomic particle with a negative charge found in shells or energy levels around the nucleus of an atom.

Neutron

A subatomic particle with no electrical charge found in the nucleus of an atom.

Ion

An atom that has gained or lost electrons, resulting in a positive or negative charge.

Cation

A positively charged ion that has lost electrons.

Anion

A negatively charged ion that has gained electrons.

Isotope

Atoms of the same element with different numbers of neutrons.

Electronic Configuration

The arrangement of electrons in shells or energy levels around the nucleus of an atom.