| A | B |
|---|
| everything is made up of tiny particles | called atoms |
| atoms cannot | be destroyed |
| atoms cannot be | brokne up into smaller pieces |
| in an element | all the atoms are identical |
| atoms can join together to form | molecules |
| dfferent types of atom can | join to make compounds |
| hydrogen gas | only contains hydrogen atoms |
| oxygen gas | only contains oxygen atoms |
| atoms are made of | protons and electrons |
| electrons are | negatively charged |
| protons are | postively charged |
| neutrons have | a neutral charge |
| an element is a pure substance | that cannot be split up into simpler substances |
| all elements can be found | in the periodic table |
| density measures | how much mass there is in a fixed volume of a material |
| density is measured in | grams per cubic centimetre |
| volume = | length x width x height |
| mass is measured in | grams |
