Calcium chloride.
There is no correct chemical formula described in your question. When calcium and chlorine combine, they form calcium chloride with a formula of CaCl2.
Chlorine atoms, which are present as chloride ions.
Cl2
Because in this formula there are two chlorine atoms in each formula unit while there is only one calcium atom.
A formula unit of AgCl contains 2 atoms: 1 of silver and 1 of chlorine.
There is no correct chemical formula described in your question. When calcium and chlorine combine, they form calcium chloride with a formula of CaCl2.
Calcium chlorate has the formula Ca(ClO3)2. Therefore, there are two chlorine atoms in each formula unit.
Chlorine atoms, which are present as chloride ions.
A chlorine molecule has the formula Cl2, so it contains two chlorine atoms.
Calcium chloride contains only two elements, calcium and chlorine, while calcium chlorate contains these two elements plus oxygen. The chlorine and oxygen in calcium chlorate are combined in a polyatomic ion with formula ClO3-1.
The formula unit for calcium nitride is Ca3N2. That would be 3 atoms of calcium and 2 atoms of nitrogen, for a total of 5 atoms in a formula unit.
4
4
CaCl2
Cl3
Cl2
There are three atoms in CaCl2 (calcium chloride) - one calcium atom and two chlorine atoms. It might be argued that there are ions inside the molecule instead of atoms. In that case there is one calcium ion and two chlorine ions.