C1

• Group 7 elements are called halogens
• Halogens exist as small molecules made up of pairs of atoms with single covalent bond (diatomic molecules
• Halogens have low melting and boiling point that increases going down the group
• Halogens are poor conductors of thermal energy and electricity
• Reactivity of halogens decreases going down group
• More reactive halogen is able to displace a less reactive halogen from an aqueous solution of halide compound
• At room temperature, fluorine is a pale yellow gas
• At room temp, chlorine is a green gas
• At room temp, bromine is a red-brown liquid
• At room temp, iodine is a grey solid and easily vaporises to a violet gas
• Transition metals are good conductors of electricity and thermal energy
• Transition metals are harder and stronger with higher densities than group 1
• Transition metals have higher melting points than group 1 except mercury
• Transition metals are less reactive than group 1 metals
• transition metals react slowly or not at all with oxygen and air at ordinary temps
• transition metal form positive ions with various charges
• Transition metal compounds are often brightly coloured
• Transition metals are used as catalysts
• Elements in group 0 are unreactive and don't easily form molecules because they have stable electronic configurations
• the noble gases are group 0 elements
• The noble gases have 8 electrons in their outershell except helium which has 2
• The boiling points of noble gases increases going down group
• Alkali metals are group 1 metals
• group 1 metals are very reactive elements with oxygen they form layer of oxide on surface of metal
• group 1 metals react with water to produce hydrogen gas and metal hydroxides
• alkalis at room temp are soft solids with low melting and boiling points decreasing going down the group
• group 1 metals have low densities lithium, sodium and potassium float on water
• Group 1s metal hydroxides are soluble in water forming colourless solution with high pH
• Group 1 metals react with halogens to form white or colourless salt crystals
• Going down group 1 reactivity increases
• When metals react they lose electrons so reactivity increases going down the group as there is less force of attraction between outermost electrons and nucleus so it is easier to lose electron
• When non-metals react they gain electrons so reactivity decreases going down group as attraction between valence electrons and nucleus decreases