Question

What is the atomic number of K?

Answer 1

Hint: Every atom element in the periodic table has a symbol, so the K symbol is used to represent the potassium element. It is the element of alkali metal, i.e., group 1 and period 4. There are 19 electrons and protons in potassium.

Complete answer:
All the substances of nature are made up of elements that are arranged in the periodic table. So, in the periodic table, all the elements are represented with the symbol. The given symbol is K and it is used to represent the potassium element. The potassium element is the member of group 1, i.e., alkali metals and it lies in period 4.
So, the atomic number is 19 and its mass number is 40 or exactly 39.098. Therefore, it has 19 electrons, so the configuration will be:
$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^1$
Its last electron enters the s-orbital that’s why it is an s-block element. It is a very reactive element and a metal. It is reactive because there is only one valence electron that can be released to complete its octet, so its oxidation state is +1. It has very little electronegativity.
Its melting point is ${63.5}^{\circ }C$ and its boiling point is ${759}^{\circ }C$, its density is less than (0.828 $g/c{m}^3$). It is a soft metal as it can be cut with a knife on applying a small pressure.
So, the atomic number of K is 19.

Note:
Potassium is a very important element in our body which performs vital reactions in our body, helps in hormone secretion and action, maintains the blood pressure, fluid and electrolyte balance, etc.