Sodium and potassium are stored under oil. Chlorine and bromine are coloured. Neon does not react at all. In this course we meet the families of the table, and we use the table to predict what an element will do.
3 lessons, about 1 h 15 min3 simulations10 problems6 practice questionsPython in every lesson
Group 1 has the alkali metals. They are soft, they have one outer electron, and they react with water to give hydrogen and an alkali. They become more reactive down the group. Group 2 has the alkaline earth metals, with two outer electrons. They are harder and less reactive than their neighbours in group 1.
Group 17 has the halogens, which are non-metals with seven outer electrons and valency 1. They get darker and less reactive down the group, and a more reactive halogen displaces a less reactive one from its salt. Group 18 has the noble gases, which have full outer shells and do not react.
We can use the table to predict the valency, formulae, reactivity and nature of an element from its position, and to estimate a property from its neighbours in the group. The transition metals are in the middle, and hydrogen is hard to place.
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