Question

Atomic number of iron is 26 . It's electronic configuration would be 2,8,8,8 according to 2n^2 . Why it is not a inert element ?

Answer 1

Dear Student,

For any atom to be inert, electrons in 1st shell should be 2, in 2nd shell should be 8, in third shell should be 8 and in fourth shell should be 18. But in valence shell of Fe (in fourth shell), only 8 electrons are present. So it is not an inert element. As Krypton's electronic configuration is 2,8,8,18 and it is noble gas.