an anion -ve charge also a cation +ve charge
Cat-ion
A positive ion is formed when atoms lose electrons. When a cell gains an electron it becomes negative
Negatively charged anions are formed.
ion attraction
The ion formed by chlorine is the "chloride" ion
an anion -ve charge also a cation +ve charge
Hydroxonium H3O+ ion is formed.
+1 Na+ ion is formed
Fluoride Ion
The ion formed by a calcium atom is called a calcium ion, which has a 2+ charge.
The overall oxidation number of an ion is indeed the charge. Na+, sodium is +1 ON, Cl-, chlorine is -1 ON. For a polyatomic ion the charge is the sum of the oxidation numbers of the consituent atoms. For example NH4+ ; N is -3, H is +1 so overall ON is +1 same as the charge.
an ionic bond