(40) GCSE Chemistry Revision "Elements, Compounds and Mixtures"

Element

A substance consisting of atoms that all have the same number of protons; each element is represented by a unique symbol in the periodic table.

Compound

A substance formed when two or more different elements are chemically combined in fixed proportions.

Element

A substance consisting of atoms that all have the same number of protons; each element is represented by a unique symbol in the periodic table.

Compound

A substance formed when two or more different elements are chemically combined in fixed proportions.

Mixture

A combination of two or more substances that are not chemically combined and can be separated by physical means.

Molecule

A group of atoms bonded together, which can consist of the same or different elements.

Fixed Proportions

The specific ratio of elements in a compound, such as 1 atom of magnesium for every 1 atom of sulfur in magnesium sulfide.

Periodic Table

A tabular arrangement of the chemical elements, organized by their atomic number.

Chemical Reaction

A process that involves the rearrangement of the molecular or ionic structure of a substance, resulting in the formation of new substances.

Physical Separation Techniques

Methods used to separate the components of a mixture without altering the chemical composition, including filtration, distillation, crystallization, and chromatography.

Example of a Compound

Methane (CH4), which consists of carbon and hydrogen atoms chemically combined.

Example of a Molecule

Oxygen (O2), which consists of two oxygen atoms chemically bonded.