Why are ionic compounds usually between metals and nonmetals?

Nonmetals lose electrons to gain a negative charge and form anions, whereas metals lose electrons to gain a postive charge and form cations.

Atoms that gain or lose electrons are called ions and can have a negative charge or a postive charge.

Explanation:

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.