Atoms and Elements

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
All substances are made of . Each atom has a central which consists of protons and . The nucleus is surrounded by orbiting . The atoms of each element are represented by a different chemical . An is a substance that only contains one type of atom. A is a substance that contains two or more elements than have chemically combined. Elements are arranged in the periodic . The periodic table contains groups of elements which have similar . When atoms are chemically combined they are held together by chemical . The bonds can be formed in different ways by atoms sharing electrons, giving electrons, or by electrons


watermolecule.png




This is a water . It has two atoms and one atom. They have chemically combined to form a .


co2molecule.png


This is a carbon molecule. It consists of one atom and two atoms.