F.4 chem..calculation..and~~

The information of isotopes of three elements A, B and C are shown below.

A has 8 protons and 8 neutrons.
B has 11 protons and 11 neutrons.
C has 17 protons and 18 neutrons.

a) Show the electronic arrangements of the three elements.

b) Elements A and B react to form a compound X.
(i) Write the chemical formula of X.
(ii) Calculate the formula mass or relative molecular mass of X.

c) Elements A and C react to form a compound Y.
(i) Write the chemical formula of Y.
(ii) Calculate the formula mass or relative molecular mass of Y.