Question

The electronic configuration of element with atomic number is 14
A.2,6,6
B.4,6,4
C.2,4,8
D.2,8,4

Answer 1

Hint:The electronic configuration is given by K, L, M shell and we need to classify it here. The energy of the shell is inversely proportional to the principal quantum number. The shell with the lowest energy has the least radius and is most close to the nucleus. The K shell is thus of the lowest energy and thus the progressive increase.

Complete step by step answer:
The maximum number of electrons in a given shell is given by the formula of 2n2 where n is the number of the energy shells or energy level. Hence for K=1 the number of electrons present is 2. In case of L=2 the number of electrons present is 8 for M the number of electrons present is 18.
The maximum number electrons in any subshell cannot be more than 8 in any of the orbits even if it has a capacity to take up more electrons according to the first rule.
It is not necessary for a new shell to form after completing itself before another but it starts forming just after the next shell is filled.
Thus, for atomic number 14 we have
 K L M
 2 8 4
This is because in the 14 electrons the first 2 electrons enter the K shell the net 8 electrons find place in the L subshell and the final left 4 shell are present in the M shell.
Thus, option D is the correct one 2,8,4.

Additional information:
The 4 electrons present in the outermost shell is that they exist in group 14. This system is applicable until atomic number 20.


Note:
we need to be careful of the type of configuration if it has been s, p, d, f configuration system the distribution is totally different in that case. We need to understand that the electrons are filled in such a manner that each subshell has a complete octet. When the subshell is complete then the atom is highly stable. Hence we apply this rule that once 8 electrons are in a particular shell we move on to the next.