question_answer 8)

Predict the formulae of compounds which might be formed by the following pairs of elements: (a) silicon and bromine (b) aluminium and sulphur  

Answer:

(a) Silicon belongs to group 14 having four electrons in the valence shell while bromine belongs to group 17 with valence electrons 7. It means silicon shows tetravalency while bromine shows monovalency. Therefore, the formula of the compound formed is\[SiB{{r}_{4}}\]. (b) Aluminium belongs to group 13 showing valency 3 while sulphur belongs to group 16 showing valency 2. Hence, the formula of the compound is\[A{{l}_{2}}{{S}_{3}}\].