KEY POINTS
Atomic no. = no. of protons
•No. of protons = no. of e- (For neutral )
•No. of neutron = Mass no. - atm no.(or no. of p)
Ex1- Atm no. =19
--->■ therefore no. of proton also 19
ii)no. of neutron=mass no. - atomic no.
=39 - 19
=20
iii) no. of e=no of proton (for neutral) ex He Ar H
□●■for charged species(ex Li+,cl-)
no. of e = no. of proton +/- charge
a))if charge is + then subtract that charge from proton then you will get no. of e
Ex K+
no. of e = no. of proton -1
=19-1=18
b)if charge is -ve then add that charge to no. of proton then we will get no.of e
Ex- cl-
no. of e- = no. of proton+ 1
=17+1=18
THANK YOU
