What is the usual manner of chemical union between inorganic compounds?

The correct answer identifies that non-metals typically gain electrons while metals lose them during the formation of chemical unions between inorganic compounds. In ionic bonding, which is a common form of union between metals and non-metals, metals have a tendency to lose electrons due to their lower electronegativity and higher energy levels of their outer electrons. This loss of electrons results in the formation of positively charged ions (cations). On the other hand, non-metals, which are generally more electronegative and have a stronger affinity for electrons, tend to gain the electrons that the metals lose, resulting in negatively charged ions (anions).

This electron transfer creates an electrostatic attraction between the oppositely charged ions, leading to the formation of ionic compounds. Therefore, the statement regarding non-metals gaining electrons and metals losing them accurately captures the fundamental process involved in the chemical bonding of these inorganic compounds through ionic interactions.