Question

Write the electronic configuration of the elements whose atomic number are 5,7,17and19respectively

Answer 1

The element with atomic number 12 is Magnesium. It has 12 electrons:
2 electrons in the 1st orbital in an s-shell
8 electrons in the 2nd orbital: 2 in an s-shell and 6 in the p-shell
and 2 in the 3rd orbital, an s-shell.

You can use the Aufbau principle to help with the order.

Answer 2

Z = 5
2,3
z= 7
2, 5
z= 17
2, 8, 7
z = 19
2,8,8,1