Answer:
2 loss of electrons.
Explanation:
An atom of any element either metal or nonmetal form ions by losing or gaining electron. This is because protons are embedded in the nucleus with neutrons and electrons are found in different orbits surround the nucleus.
Metals have 1 or 2 or 3 electrons in their outermost shell which is called valence shell and electrons in these shell is called valence electron.So they lose electrons to form ions.Metals lose electrons and positively charged ions called cations.
Whereas nonmetals have 5 or 6 or 7 electrons in their outermost shell so they gain electrons to form ions.
For example Aluminium is a metal having electronic configuration (2,8,3). That means aluminium have 3 electrons in its valance shell so it loses its electrons to become a positively charged ion.
Another one is Sodium a metal having electronic configuration (2,8,1). That means aluminium have 1 electrons in its valance shell so it loses its electrons to become a positively charged ion.