Question

The atomic number of an element is 9.write its electronic configuration and find its valency.                                         ​

Answer 1

Answer:

Given 2,8,7 in this first shell can have 2 electrons where as second shell can have 8 electrons 2 in s orbital and 6 in p orbital.

Hence remaining 7 must be only in third shell as third shell has capacity of 18 electrons.

Here in valence shell we have 7 electrons in which 2 are in s orbital and 5 are in p orbital in which 1 is unpaired. Hence valency electrons is 7 for atomic number 17 that is chlorine and valency is 1 as it has to get one electron to get octet configuration

Answer 2

Answer:

Fluorine  is most electronegative and nitrogen is least electronegative.

Fluorine has 7 valence electrons.

valency of fluorine is 1.

hope it will be easy to understand