protons and electrons are both always the atomic number which is 9 in this case.
For neutrons you subtract the atomic number (9) from the weight of the atom (18.998) some teachers will want you to round to the nearest whole (19). We do this because the number of protons is the atomic number so if you subtract the protons from the whole weight of the atom you would have the electrons and neutrons left. Since electrons weigh so little we don't have to subtract them. Weighing neutrons and electrons would be like weighing an elephant (neutrons) and then putting one marshmallow on the scale (electron).
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
The cations and anions being oppositely charged attract each other through strong coloumbic forces and form an ionic bond.
(1) Sodium is carrying +1 charge called as cation and chloride is an anion carrying -1 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(2) Sodium is carrying +1 charge called as cation and phosphate is an anion carrying -3 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(3) Sodium is carrying +1 charge called as cation and sulfate is an anion carrying -2 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(4) Sodium is carrying +1 charge called as cation and carbonate is an anion carrying -2 charge. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
(5) Potassium is carrying +1 charge called as cation and chloride is an anion carrying -1 charge. They form .
(6) Potassium is carrying +1 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(7) Potassium is carrying +1 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(8) Potassium is carrying +1 charge called as cation and carbonate is an anion carrying -2 charge. They form .
(9) Calcium is carrying +2 charge called as cation and chloride is an anion carrying -1 charge. They form .
(10) Calcium is carrying +2 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(11) Calcium is carrying +2 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(12) Calcium is carrying +2 charge called as cation and carbonate is an anion carrying -2 charge. They form .
(13) Ammonium ion is carrying +1 charge called as cation and chloride is an anion carrying -1 charge. They form .
(14) Ammonium ion is carrying +1 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(15) Ammonium ion is carrying +1 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(16) Ammonium ion is carrying +1 charge called as cation and carbonate is an anion carrying -2 charge. They form .
(17) Iron is carrying +3 charge called as cation and chloride is an anion carrying -1 charge. They form .
(18) Iron is carrying +3 charge called as cation and phosphate is an anion carrying -3 charge. They form .
(19) Iron is carrying +3 charge called as cation and sulfate is an anion carrying -2 charge. They form .
(20) Iron is carrying +3 charge called as cation and carbonate is an anion carrying -2 charge. They form .
Hunger, chemical imbalance, and blood levels are all internal issues. Cat dander on the other hand is not something the body creates or and is something in the environment. Thus, your answer is A.