When an atom of lithium Li encounters a fluorine F atom the

When an atom of lithium (Li) encounters a fluorine (F) atom, the fluorine steals an electron from lithium and the resulting ions stick together in ionic bonds When an atom of carbon (C) encounters nitrogen (N), the two may share electrons in a covalent bond. Why do some atom combinations form electron stealing ionic bonds and others form electron sharing covalent bonds? Figure 2.5 in the text and my discussion of that figure in lecture will help you.

Solution

Ionic bond: To form a stable compound complete valance electrons are transfer between atoms. When lithium encounters the fluorine there is formation of ionic bond between two atoms. In ionic bond metal compound (lithium) tended to lose the valance electrons to become a positively charged cation, whereas non-metal (fluorine) tended to accept the electrons to become an anion.

Electron configuration of lithium is 1s²2s¹ to become a stable compound it tended loose one electron to fluorine and become cation.

Electron configuration of Fluorine is [He] 2s2 2p5 to become stable compound it tended to accept one electron from lithium and become anion.

So when lithium encounters fluorine lithium will lose one electron and whereas fluorine accept that electron to form a lithium fluoride (LiF).

Covalent bond: it form between non-metallic compounds characterized by sharing of pairs of electrons between atoms and other covalent bond.

It is also called as molecular bond.

It involves sharing of electrons between the atoms.

Sharing of electrons allow them to attain equivalent of a full outer shell, corresponding to stable electronic configuration.

So when carbon encounters the nitrogen atom they share electrons between them to form covalent bond and to attain corresponding stable configuration.