Chemistry IGCSE - Atoms, elements and compounds foundation

Elements

A substance made up of only 1 type of atom

Compounds

A substance made up of 2 or more different types of atoms

Mixture

contains 2 or more elements/compounds that are not chemically bonded

Describe the structure of the atom

a central nucleus containing neutrons and protons, surrounded by electrons in shells

Relative charge and relative mass of a proton

Relative charge and relative mass of a neutron

Relative charge and relative mass of an electron

Proton number/atomic number

number of proton in the nucleus of an atom

Mass number/nucleon number

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

Electronic configuration

Group VIII (8th)

full outer shell

connection between no. of valence shell electrons and group no.

the no. of outer-shell electrons = group no. in Groups I to VII

connection between no. of occupied electron shells and period no.

the no. of occupied electron shells = period no.

Isotope

different atoms of the same element that have the same no. of protons but different no. of neutrons

Isotopes with similar chemical properties

Isotopes of the same element have the same chemical properties → same no. of electrons → same electronic configuration

Alloy

a mixture of two or more metals or metal with a non-metal