Question

calculate the number of electrons in K, L, M and N shells using 2n2 formulae​

Answer 1

Answer:

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It states that electrons fill atomuc orbitals of the lowest available energy levels before occupying higher levels. Solving the wave equation of Schrödinger for the permisdible energy levels of electrons in various atoms across the periodic table reveals that s sub orbitals of outer shells may have lower energy levels than d or f shells of inner shells, in larger atoms. In addition, Hund's rule states that if multiple orbitals of the same energy are available, electrons will occupy different orbitals singly before any are occupied doubly.

The reason why an inner shell electron may have a higher energy level than an outer shell one is the increased force of attraction from the nucleus as the atomic number increases, and a corresponding reduction in the radius of the shell.

Thus orbitals are filled in the order of increasing energy, using two general rules.

1. Electrons are assigned to orbitals in order of increasing value of (n+l), where l is the sub shell number (s=0,p=1,d=2,f=3)

2. For subshells with the same value of (n+l), electrons are assigned first to the sub shell with lower n.

So the order of orbital filling by this rule would be 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 8s, from atomic no 1 to 20.

Answer 2

Answer:

We usually fill the electrons in K,L, M and N shells as 2,8,8,8. But according to 2n square rule K, L, M and N shells can take 2, 8 , 18 and 32. Why we fill only 2,8,8,8 in K L M N shells instead of 2,8,18 and 32?