Answer:
Step-by-step explanation:
The valency of a chemical element refers to the number of electrons that it can gain or lose in a chemical reaction. The valency can also be thought of as the charge on the ion of the element.
The valencies of the compounds you have provided are:
K3PO4 (Potassium Phosphate)
Potassium (K) has a valency of +1
Phosphorus (P) has a valency of +5
Oxygen (O) has a valency of -2
Al2(SO4)3 (Aluminum Sulfate)
Aluminum (Al) has a valency of +3
Sulfur (S) has a valency of +6
Oxygen (O) has a valency of -2
NaNO3 (Sodium Nitrate)
Sodium (Na) has a valency of +1
Nitrogen (N) has a valency of +5
Oxygen (O) has a valency of -2
It's worth noting that valency of elements within a compound can be determined by the oxidation state of the element and by the chemical formula of the compound. The oxidation state is determined by the number of electrons gained or lost by the element.