Module 3 - Group 2
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describe the trend in reactivity of group 2 metals
-reactivity increases down the group
explain the trend in reactivity of group 2 metals
-shielding increases -nuclear charge increases -nuclear attraction decreases -atomic radius increases -so it is easier to lose electrons
name the different reactions of group 2
• group 2 metal + water • group 2 metal + acid • group 2 metal + oxygen • group 2 metal carbonate + acid
observations of group 2 metal + water
-fizzing/bubbling -metal disappears -heat given out (exothermic)
change in pH when group 2 metal + water
-increases
equation for group 2 metal + water
metal + water -> metal hydroxide + hydrogen
observations of group 2 metal + acid
-bubbling/fizzing -metal disappears
change in pH when group 2 metal + acid
-increases
equation for group 2 metal + acid
metal + acid -> salt + hydrogen
observations for group 2 metal + oxygen
-bright white light -colour change
change in pH when group 2 metal + oxygen
-increases
equation for group 2 metal + oxygen
metal + oxygen -> metal oxide
observations for group 2 metal carbonate + acid
-fizzing/bubbles -metal carbonate disappears
change in pH when group 2 metal carbonate + acid
-increases
equation for group 2 metal carbonate + acid
metal carbonate + acid -> salt + carbon dioxide + water
describe solubility of group 2 compounds
-the oxides of group 2 elements can react with water, releasing hydroxide ions and forming a metal hydroxide -this hydroxide is alkaline
describe the trend in solubility of group 2 compounds
-increases down the group -number of OH- ions released increases -so pH increases
describe the uses of group 2 compounds
-group 2 bases are often used as antacids for indigestion -group 2 metal barium can react with sulphate to make barium sulphate for use in barium meals, as it is insoluble in water and forms a white precipitate -calcium hydroxide is used to neutralise soil in agriculture