how to find valence electrons of an element 
plz tell with example of
tin krypton strontium and titanium

 

  
valence electrons are the lectrons present in the outermost shell of the element. they are involved in bonding with the other atom.
 
the electronic configuration of  tin, krypton and strontium and titanium and their valence electrons are as follows:
 
tin:
[kr] 4d10 5s2 5p2
 
valence electrons in titanium are 4 which are present in the outermost fifth orbital.
 
krypton:
[ar] 3d10 4s2 4p6
 
valence electrons in krypton are 8 which makes its very stable.
 
strontium:
[kr] 5s2
 
strontium has 2 valence electrons.
 
titanium:
[ar] 3d2 4s2
 
titanium has 4 valence electrons.