Key word Definition The Periodic Table – Group 1, 7 and 0 Alkali metals Elements in group 1 of the periodic Properties as you go DOWN Group 1, 7 and 0. table. Group 1 Group 7 Group 0 Ionic A compound that contains positive and Group 7 Elements compounds negative ions held together in a regular Reactivity Reactivity Unreactive • Also called the halogens. arrangement (lattice) by electrostatic increases decreases • As elements they form forces of attraction. molecules that contain Melting and Melting and Boiling point Halogens Elements in group 7 of the periodic two atoms. Boiling points Boiling points gets higher table. • E.g. Cl2 is chlorine get lower get higher Halides An ion with a 1- charge formed when a Halogen atom gains an electron. Relative atomic Relative atomic Relative atomic Reactions with non-metals Noble gases Elements in group 0 of the periodic mass goes up mass goes up mass goes up They share electrons and form table. covalent bonds Inert Not chemically reactive. Reactions with metals • Halogens form ionic bonds Group 0 Elements • Also called the noble Group 1 Elements Reactions with water with metals to form gases. • 1 electron in the Vigorous reaction to produce negative ions called halides. • Colourless gases at room outer shell. This metal hydroxide (salt) and • E.g. sodium chloride, which temperature. makes them very hydrogen gas. is an ionic structure. • All have 8 electrons in reactive. the outer shell, apart • Easily lose one Reaction with Chlorine from Helium which has 2 electron in outer Vigorous reaction when - stable full outer shell. shell to form a full heated in chlorine gas to • Unreactive. outer shell. form metal chlorides (white • They form positive salts). ions. They are very unreactive. • They’re soft. Reaction with Oxygen This means they don’t form • They have a low React with oxygen to form molecules easily, so density. metal oxide. It makes the elements are found as single shiny group 1 metal go a dull atoms. grey..