Question #e453d

1 Answer
Jan 3, 2017

The arrangement of electrons in the orbitals of an atom or molecule.

Explanation:

So basically the electronic configuration tells us which element is present in which groups, in which periods and in which block (s block, p block, d block and f block).

By knowing how many electrons are present in the shells, we can find the place of an element in the periodic table.

Q: Find the electronic configuration of aluminium?

Ans: "Al" has an atomic number equal to 13

So,

(1s^2)/"K" " " (2s^2,2p^6)/"L"" "(3s^2,3p^1)/"M"

Here "K" is the first shell, "L" is the second, and "M" is the third shell (the valence shell).

As n = 3, "Al" is present in the "3rd" period. Since the total number of electrons in the valence sub-shells are

2+1=3

it must be present in group lllA (in Roman Numerals). or group 13. and in the last shell, we have a "p" so we can say that aluminium is present in the p block.

https://www.youtube.com/watch?v=Gp46VYoexVghttps://www.youtube.com/watch?v=Gp46VYoexVg