CHEMISTRY 1

Lab rules

Safety guidelines that everyone must follow in the science laboratory.

Biology

The study of living things.

Chemistry

The study of substances and how they react.

Physics

The study of energy, forces, and motion.

Independent variable

What you change in an experiment.

Dependent variable

What you measure in an experiment.

Controlled variable

What you keep the same in an experiment.

Safety precautions

Actions taken to avoid danger and injury.

Atom

The smallest particle of an element that still behaves like that element.

Subatomic particles

The three particles that make up atoms: protons, neutrons, and electrons.

Proton

A positively charged particle in the nucleus.

Neutron

A neutral particle in the nucleus.

Electron

A negatively charged particle found outside the nucleus.

Nucleus

The centre of the atom containing protons and neutrons.

Mass number

The total number of protons + neutrons.

Atomic number

The number of protons in an atom (also equals the number of electrons in a neutral atom).

Electron arrangement

How electrons are arranged in energy levels (shells) around the nucleus.

Valence electrons

Electrons in the outer shell that take part in reactions.

Ion

A charged atom or group of atoms formed when electrons are gained or lost.

Cation

A positively charged ion (forms when metal atoms lose electrons).

Anion

A negatively charged ion (forms when non-metal atoms gain electrons).

Electron transfer

Movement of electrons from metal atoms to non-metal atoms during reactions.

Ion charge

The overall positive or negative charge on an ion.

Monoatomic ion

An ion made from a single atom.

Polyatomic ion

An ion made from a group of atoms with an overall charge.

Chemical formula

A combination of symbols and numbers showing the elements and the ratio of atoms in a compound.

Neutral compound

A compound where the total positive charge equals the total negative charge.

Element

A substance made of only one type of atom.

Mixture

Two or more substances not chemically joined.

Molecule

Two or more atoms bonded together.

Compound

Two or more elements chemically joined in a fixed ratio.

Reaction

A process where new substances (products) are formed from starting substances (reactants).

Reactants

The substances present at the start of a reaction.

Products

The new substances formed during a reaction.

Chemical change

A change that forms new substances.

Physical change

A change in state or appearance; no new substance forms.

Conservation of matter

Matter cannot be created or destroyed in a reaction.