Materials Vocabulary (KCC Yr 9 Science 2025)

Element

A pure substance made of only one kind of atom. Elements are the building blocks of other substances and can be found on the periodic table.

Metals

Elements that are good conductors of electric current and heat. On the left of the periodic table.

Non-metals

elements that are usually dull in appearance, poor conductors of heat and electricity, gases at room temperature. On the right of the periodic table.

Metalloids

Elements that have properties of both metals and nonmetals. Between the metals and non-metals on the periodic table.

Examples of substances that are elements

Gold, pure water, pure oxygen.

Examples of metals

Iron, copper, sodium, magnesium.

Examples of non-metals

Oxygen, carbon, chlorine

Examples of metalloids

boron

Monatomic elements

Elements that exist in nature as single atoms. Eg. helium and argon.

Diatomic elements

Elements that exist in nature as two atoms of the same bonded together. Eg. chlorine (Cl2) and nitrogen (N2).

Lattice Elements

Elements that arrange themselves in large, complex crystal structures. Eg. diamond.

Compounds

Substances that contain atoms of two or more different elements chemically bonded in a fixed ratio.

Mixtures

Two or more pure substances (either elements or compounds) combined but not chemically bonded together. Alloys are mixtures of a metal and other metals or non-metals.

Pure substances

Substances that are either elements and compounds.

Impure substances

Substanes that are homeogenous and heterogenous mixtures.

Solids

A state of matter in which the object has a fixed shape and volume.

Liquids

A state of matter in which the object has a fixed volume but a variable shape.

Gas

A state of matter ion which the object has a variable shape and variable volume.

Diffusion

The process of gases expanding to fill their container.

Melting

State change from solid to liquid

Evaporation

State change from liquid to gas.

Condensation

State change from gas to liquid.

Freezing/solidification

State change from liqiud to solid.

Sublimation

State change from solid to gas.

Deposition

State change from gas to solid.

Proton

positively charge subatomic particle found in the nucleus.

Neutron

neutral subatomic particle found in the nucleus.

Electron

negatively charged subatomic partcile found orbiting the nucleus

Atomic number

the number of protons in an atom. Found on the periodic table.

Mass number

the sum of the number of neutrons and protons in an atomic nucleus.

Isotope

A form of an element that has the same number of protons but a different number of neutrons

Ion

A form of an atom that has a positive or negative charge due to electrons and protons not being equal

Valence shell

The outermost electron shell in an element

Electron configuration

the arrangement of electrons in an atom

Electron shell diagram

Diagram showing electrons in their shells around the nucleus of an atom.

Ground state of an atom

The lowest possible energy state of the electrons in an atom.

Annealing

Heating a metal to a specified temperature where recrystallisation occurs and allowing it to cool down slowly to room temperature

Quenching

Heating a metal to a specified temperature where recrystallisation occurred and quickly cooling it down in water or oil bath

Tempering

Heating a quenched metal to below recrystallisation temperature and allowing it to cool down in the air

Metals

Dense, ductile, malleable substances with high melting and boiling points that are generally good thermal and electrical conductors

Ductile

A term used to describe a material that can be pulled out into a long wire.

Malleable

capable of being beaten into shape

Lustrous

Shiny

Metal Alloys

Mixture of at least one metal and one other substance to improve its properties.

Covalent bond

A bond between non-metal elements that involves the sharing of electrons to gain a full outer shell.

Covalent molecular compounds

A compound composed of two or more nonmetal elements bonded in individual sub-units (e.g. water, carbon dioxide)

Covalent network compounds

Non-metal elements or metalloids covalently bonded in a huge 3-D network (e.g. diamond, sulfur, silicon)

Allotrope

Different physics forms of the same element (e.g. graphite, charcoal and diamond)

Properties of covalent compounds

These vary but, most have low melting and boiling points (but there are lots of exceptions), most are poor conductors of electricity, cakey and crumbly (if solid) and dull with no shine or lustre.

Properties of ionic compounds

Brittle, hard with very high melting and boiling points. Conduct electricity when dissolved in water but not as solids.

Examples of ionic compounds

Sodium chloride (NaCl), copper sulfate (CuSO4), potassium nitrate (KNO3).

Examples of covalent compounds

Water (H2O), carbon dioxide (CO2), sulfur (S8).