memory trick for atomic weight

 

Here are some technique to memorize name of elements and atomic weight of elements. It is specially concerned for the elements having atomic number between 20 to 30. First of all, lets discuss how to remember name and symbol of elements from atomic number 21 to 30.

सचिन,तेन्दुल्कर,बिराट कोली,क्रिश गेल,मे , फिर,कोही,नयाँ, सेन्चुरी, जमाएगा        

Now I'm going to tell you three rules to remember atomic weight. they are 

i) 2n rule,

ii) (2n+1) rule  and

 iii) (2n +x) rule 

2n and  (2n+1) rule

First two  rules are applicable for the elements having atomic number up to 20. 2n rule is applicable for even atomic number and (2n+1)  rule is applicable for odd atomic number. However, Be follows (2n+1) rule, nitrogen follows 2n rule regardless the atomic no. Atomic weight of Cl is 35.5 and that of Ar is 40. 

even atomic no = 2n rule 

odd atomic no = 2n +1 rule

Exceptions  :   H, Be, N, Cl  & Ar

(2n+x) rule 

It  is applicable to memorize atomic weight of elements from Sc to Zn. It is easiest trick that gives whole number values only. where,

Atomic wt = 2n + x                                              

where, n  = atomic number  of element and   

x = Three वटा  45 three 55          

That is, x = 3, 4,5,4,5,4,5, 3,5,5