Answer: (b). Atoms transfer electrons to form cations and anions.
Explanation:
Covalent compounds are formed by sharing of electrons takes place between non metals.Ionic compounds are formed by transfer of electrons between metals and non metals.
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Sodium atom has oxidation number of +1.
Electronic configuration of sodium:
\([Na]=1s^22s^22p^63s^1\)
Sodium atom will loose one electron to gain noble gas configuration and form sodium cation with +1 charge.
\([Na^+]=1s^22s^22p^63s^0\)
Chlorine atom has oxidation number of -1.
Electronic configuration of chlorine:
\([Cl]=1s^22s^22p^63s^23p^5\)
Chlorine atom will gain one electron to gain noble gas configuration and form chloride ion with -1 charge.
\([Cl^-]=1s^22s^22p^63s^23p^6\)
In sodium chloride the one electron from sodium metal gets transferred to chlorine atom and thus form an ionic bond.
