Question

What is the octet rule?
A. A rule that says atoms like to have full valence shells of eight electrons
B. A rule that says electrons reside in the nucleus of atoms
C. A rule that says atoms like to have empty valence shells
D. A rule that says atoms must bond eight times with other atoms
E. A rule that says electrons orbit atoms in energy shells

Answer 1

Hint: The octet rule refers to a very important chemical rule of thumb. Moreover, this rule means the observation that elements bond in a very way such that every atom contains a particular number of electrons within the valence shell.
- The octet rule refers to a very important chemical rule of thumb.

Complete Solution :
- Atoms of various elements tend to gain, lose or share valence electrons during the formation of molecules such that there are eight electrons or octets in their valence shells. This octet rule or electronic theory of the chemical bonding was proposed by Kossel and Lewis in 1916.
- The octet rule refers to a crucial principle that the atoms which have bonded share eight outer electrons. This certainly implies that the atom’s valence shell contains a resemblance with noble gas.
- The octet rule states that the atoms prefer to have eight electrons only in their full outer shells. For achieving eight electrons in their outer shells, atoms would gain or lose the valence electrons.
- Furthermore, the atom does this by bonding with one another. Moreover, these bonding can be between the same identical element or with different elements.
- Two notable exceptions to this octet rule are helium and hydrogen. This is often because both have two valence electrons present within the outer shells. So they have complete valence shell configuration.
So, the correct answer is “Option A”.

Note: Another limitation of the octet rule in Period 3 is that the elements present on the right side of the periodic table contains d orbitals. The d orbitals may sometimes accept the electrons and thus allow other elements to have more than an octet. Examples of such elements are phosphorus and sulfur.