Question

What is the atomic number of iron?

Answer 1

Hint: Atomic number of any element is the amount of total electrons which is equal to the total protons in that atom. The periodic table consists of elements arranged in the increasing order of their atomic numbers. Iron has a symbol of Fe that comes under d – block elements and is placed with transition metals.

Complete answer:
Atomic number of any element tells us the number of protons of that atom which is equal to the number of electrons in that atom. Through the atomic number, which is the number of electrons, the electronic configuration of elements is determined. The electronic configurations consist of filling of electrons in various orbitals from lower energy level to higher energy level.
The electronic configuration of iron is, $Fe=1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}4{{s}^{2}}3{{d}^{6}}$
Through this configuration the total number of electrons in iron is found to be 26. So, 26 is the atomic number of iron. Also, from the periodic table we can see that iron has an atomic number of 26 as follows:

The numbers written above the elements show us the atomic numbers.
Hence, the atomic number of iron is 26.

Note:
The elements in the periodic table are arranged according to their atomic numbers. Iron denoted as Fe is the element of the d – block as it has its valence electrons entering into the d – orbital. The total number of electrons which is also the number of protons are the atomic number of an atom, while the sum of protons and neutrons are the atomic masses of atoms.