How many core electrons are presentin `._(19)K` ?
Hint `: 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(1)`

How many valence electrons are present in sodium with atomic number 11 ? Hint : 1s^(2) 2s^(2) 2p^(6) 3s^(1)

An element having electronic configuration 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(1) forms:

An element having electronic configuration is 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(1) will form:

The element with the electronic configuration 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(10) 4s^(1) is

An element having electronic configuration is 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3P^(6) 4s^(1) will form:

In an atom the number of electrons in N - Shell is equal to the number of electrons in K, L and M shells. Answer the question. How many electrons are there in its outermost shell ? Explanation : K = 1 s^(2) (2) electrons L = 2s^(2) 2p^(6) (8) electrons M = 3s^(2) 3p^(6) 3d^(10) (18) electrons Total (28) electrons N = 4s^(2) 4p^(6) 4d^(10) 4f^(10) (28) electrons To fill 4f^(10) , 1s^(2) , 2s^(2) 2p^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(2) 3d^(10) 4p^(6) 5s^(2) 4d^(10) 5p^(6) 6s^(2) should be filled Hence , the electronic configuration is 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(2) 3^(10) 4p^(6) 5s^(2) 4d^(10) 5p^(6) 6s^(2) 4f^(10) .

In an atom the number of electrons in N - Shell is equal to the number of electrons in K, L and M shells. Answer the question. Write the electronic configuration of the elements. Explanation : K = 1 s^(2) (2) electrons L = 2s^(2) 2p^(6) (8) electrons M = 3s^(2) 3p^(6) 3d^(10) (18) electrons Total (28) electrons N = 4s^(2) 4p^(6) 4d^(10) 4f^(10) (28) electrons To fill 4f^(10) , 1s^(2) , 2s^(2) 2p^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(2) 3d^(10) 4p^(6) 5s^(2) 4d^(10) 5p^(6) 6s^(2) should be filled Hence , the electronic configuration is 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(2) 3^(10) 4p^(6) 5s^(2) 4d^(10) 5p^(6) 6s^(2) 4f^(10) .