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The Lewis structure describes the types of atoms in a molecule and how the atoms

are bonded to one another. An example of the Lewis structure of the element
1
1H = 1s . Valence electrons = 1
5
2
6
2
2
17O = 1s 2s 2p 3s 3p . Valence electrons = 7

Figure. Lewis structures of H, Cl and HCl compounds

H elements have 1 valence electron so they need an additional electron to fulfill the
duplet rule. The Cl element requires an additional 1 electron to fulfill the octet rule.

Thus, the elements H and Cl each donate 1 electron to be shared.

B. Bonding Electron Pairs (PEI) and Lone Electron Pairs (PEB)

In the formation of covalent bonds, either single covalent bonds or double covalent
bonds, it is not certain that all of the valence electrons are shared. The pair of

electrons that are shared is called the bonding pair (PEI) and the pair of valence

electrons that are not involved in forming a covalent bond is called the lone pair
(PEB).

Figure. Bonding electron pairs and lone electron pairs in compounds NH3.

Covalent Compound| 11