Compounds and mixtures

Particle diagrams can be used to represent atoms. Each circle represents an atom, and circles of different sizes or colours are used to represent different elements. Diagram A represents . . .

• unbonded atoms of one element

• molecules of one element

Diagram B represents ...

• unbonded atoms of one element

• molecules of one element

The photograph represents ...

• unbonded atoms of one element

• molecules of one element

• atoms of a compound

• molecules of a compound

The photograph represents ...

• unbonded atoms of one element

• molecules of one element

• unbonded atoms of two elements

• molecules of two different elements

An atoms is ...

• the smallest unit of matter

• formed when two or more atoms are chemically bonded together

• formed when atoms of two or more elements are chemically bonded together

Elements are ...

• pure substances formed from one type of atom only

• formed when two or more atoms are chemically bonded together

• formed when atoms of two or more elements are chemically bonded together

Molecules are ...

• pure substances formed from one type of atom only

• the smallest units of matter

• formed when two or more atoms are chemically bonded together

Compounds are ...

• pure substances formed from one type of atom only

• the smallest units of matter

• formed when atoms of two or more elements are chemically bonded together

Mixtures are ...

• pure substances formed from one type of atom only

• formed from two or more substances, mixed together without forming chemical bonds

• formed when two or more atoms are chemically bonded together

Tilly has written a definition of a molecule. She states that "Molecules are formed when two or more elements are chemically bonded together". Her friends are discussing this definition. Who is correct?

• Abigail

• Thomas

• Charlie