State the number of atoms present in each of the following chemical species

(a) CO₃^2-

(b) PO₄^3–

(c) P₂O₅

(d) CO

(a) The number of atoms in CO₃^2- = the atom of C + the atom of oxygen

= 1 + 3

= 4

(b) The number of atoms in PO₄^3– = the atom of P + the atoms of oxygen

= 1 + 4

= 5

(c) The number of atoms in P₂O₅ = the atoms of P + the atoms of oxygen

= 2 + 5

= 7

(d) The number of atoms in CO = the atom of C + the atoms of oxygen

= 1 + 1

= 2