1.1. A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes 3

Atom

The smallest part of an element that can exist.

Chemical Symbol

A representation of an atom of an element, e.g. Na for sodium.

Compound

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

Mixture

A combination of two or more elements or compounds not chemically combined, where properties remain unchanged.

Filtration

A method used to separate mixtures by physically removing larger particles.

Crystallisation

A technique to separate soluble solids from a solution by forming crystals.

Plum Pudding Model

An early model of the atom, proposing it as a ball of positive charge with negative electrons embedded.

Alpha Particle Scattering Experiment

An experiment that led to the conclusion that mass is concentrated in the nucleus of an atom.

Electron

A negatively charged subatomic particle with a very small mass.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

A subatomic particle found in the nucleus of an atom that has no charge.

Relative Atomic Mass

An average mass of an element's isotopes taken into account their abundance.

Isotope

Atoms of the same element that have different numbers of neutrons.

Mass Number

The sum of the number of protons and neutrons in an atom.

Nucleus

The central core of an atom, containing protons and neutrons.

Electrons Shells

Levels around the nucleus where electrons are found.

Energy Levels

The specific distances from the nucleus where electrons can occupy.

Relative Charge of Proton

+1

Relative Charge of Neutron

0

Relative Charge of Electron

-1

Atomic Number

The number of protons in an atom of an element.