Tricks to find out Atomic number

ATOMIC number tricks: S-block elements P-block elements d-block elements =>Memorize Atomic numbers of period 2 elements only than use these two formulas. How to find out atomic number of elements in periodic table quickly?

These are the ways you can find out atomic no. in periodic table much quickly than any other methods.

S-block elements Formula 1:-. 8,8,18,18,32 Use this formula for group 1 ,2 and 18. For example:- Let me find group 1 atomic numbers. Li (Lithium) atomic no=3 Now use formula 8,8,18,18,32 ->add One 8 with Li Atomic no =3 So 8+3=11 this is Na(sodium) Now add next digit of formula with Na= 11 So 11+8=19 (k)this is potassium Now add next digit of formula with potassium atomic no So 19+18=37 this is Rubidium Apply same method for group 2 and 18.... P-block elements: Formula 2:- 8,18,18,32 Remember this formula use for group 13,14,15,16 and 17 Same method like first . Let me find atomic numbers of group 13 Boron atomic no=5 So add one 8 with boron atomic no So 8+5=13(Aluminum) Now add next digit 18 with 13 so 18+13=31 Gallium... Apply for other groups also. d-block elements Formula:18,18,32 How to use? Example: Scandium Sc :21 So add 18 with 21 18+21=39 which is atomic number of yattrium Y.... Apply for other elements down the groups....

Courtesy: General Chemistry Notes

Periodic table