Why is the symbol [Ar] used in the electron configuration of potassium, and what does it represent?

To denote a stable inner configuration and it represents argon

Explanation:

The symbol [Ar] used in the electron configuration of potassium represents the inner electronic configuration of the element.

This argon atom is stable octet with completely filled shells. Most noble gases are used to write the electronic configuration of other atoms. The inner atomic orbitals of elements are similar to those of nearby noble gases.

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).