Question

The shell closest to the nucleus of an atom is?
a) $M$
b) $N$
c) $L$
d) $K$

Answer 1

The structure of atoms has been a subject a subject of quite research.Various physicists proposed their own models however many of them failed to stand the laws of physics.After much debates it has been agreed upon that an atom consists of various sub-species like protons,electrons and neutrons.

Complete answer:
The atom consists of various sub-species primarily the protons,neutrons and electrons.All of them are an essential part of the atom.A physicist named Bohr proposed a theory which pretty much explained the arrangement of electrons in an atom thus giving the way to future research to take place.Let us look at Neil Bohr’s atomic model:-
-The Bohr model proposed that the electrons in an atom follow a definite path called orbits around the nucleus.These orbits differed in energy
-Bohr described the term energy levels (or shells) to describe these orbits of distinct energy and said that the energy of an electron is quantized which means that electrons can have a discrete energy level.These energy levels were assigned mnemonics which are as follows:-
$n = 1 = K - shell$
$n = 2 = L - shell$
$n = 3 = M - shell$
$n = 4 = N - shell$
and so on. Where n represents the principal quantum number or the number of energy shells.
-Bohr discovered that the closer an electron is to the nucleus, the less energy it requires whereas the farther away it is, the more energy it requires.
Hence according to this discussion the shell closest to the nucleus is $K$ and so the correct option is (d).

Note:
Bohr's atomic model was quite advantageous at it’s time.It correctly explained the stability of an atom since an electron revolving in a particular orbit cannot lose energy.Hence electron won’t be emitted as long as the electron remains in one of its energy levels.