Elements, Compounds and MixturesSarah Jones

csironewsblog.com

AtomsAll substances are made of ATOMS.

Water – hydrogen and oxygen atomsPlastic – carbon and hydrogen atomsPlants – carbon, nitrogen, hydrogen, oxygen and sulfur atoms

Elements• There are about 100 substances that are made

up of just one type of atom.• These are elements.

Helium CarbonCopper

Molecules• In some elements, the atoms are joined in

groups of two or more – this is called a molecule.

O2

Other elements that contain atoms joined in molecules are hydrogen, nitrogen, chlorine and bromine.

Symbols for Elements

H – HydrogenC – CarbonF – FluorineO – OxygenN – NitrogenI – Iodine

Li – LithiumAl – AluminiumHe – HeliumPb – LeadAu – GoldAg - Silver

Compounds

• A compound is the substance produced when two or more elements combine in a chemical reaction – they are also molecules.

H2OCO2

The Periodic Table

• The periodic table is a list of all of the known elements. The elements are arranged according to the similarities in their properties.

http://www.infoplease.com/dk/science/encyclopedia/periodic-table.html