Question

name of the compounds NiS Mg (NO3)2 and Pb3 (PO4)2

Answer 1

NiS is Nickel Sulphide.

Mg$NO_{3}$ is Magnesium Nitrate

$Pb_{3} (PO_{4})_{2}$  is Lead Phosphate.


Hope it helped!
NISHTHA.

Answer 2

Mg2+ and

PO4^3- . The charge of Mg which is 2 will interchange with PO4 's charge which is 3(because in compound formation,the negative sign is always ignored) to yield the compound Mg3(PO4)2 .Take care