Predict the formulae of the stable binary compounds that would be formed by the following pairs of elements (a) silicon and oxygen (b) aluminium and bromine ( c ) calcium and iodine (d) element 114 and fluorine (e ) element 120 and oxygen.

Explanation

(a) Silicon belongs to group 14. it has four valence electrons and hence its valence= 4 Oxygen belong to group 16. It has six electrons in the valence shell and hence its valence =8-6 =2 . Therefore the formula of silicon oxide= `SiO_(2)`.
( b) Aluminium belongs to group 13. It has three electron in the valence shell and hence its valence =3.
Bromine belongs to group 17. It has seven electrons in the valence shell and hence its valence =8-7 =1
Therefore formula of aluminium bromide= `AIBr_(3)`
(c ) Calcium belongs to group 2. It has two -electrons in the valence shell and hence its valence =2 .Iodine belongs to group 17. It has seven valence electrons and hence its valence =8-7=1.
Therefore formula of calcium iodic= `Cal_(2)`
(d )In the 7th period the 4th transition series ends at element with Z =112, therefore filing of 7p- subshell will begin with element Z=113 .Hence element with Z= 114 will have two electrons in 7p- orbitals and two electrons in 7 s-orbital .In other words the element Z= 114 will lie in group 14 and hence its valence =4
fluorine belongs to group 17 with seven valence electrons and hence its valence =8-7=1
Therefore formula of compound formed by element 114 and fluorine is `MF_(4)` where M represents the element
(e) The 7th period ends at element with Z= 118. Therefore filling of 8th shell i.e., 8 s-orbital will begin with element Z= 119 and consequently with Z= 120 will belong to group 2 and its valence will be =2
Oxygen belongs to group 16 with six valence electrons and hence its valence =8-6=2.
Therefore formula of compound formed by element Z= 120 and oxygen will be MO where M respresent element.