gen chem question

[elz787]

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so there's this question in my kap book "which are the valence electrons of elemental selenium" the answer is : selenium has 6 valence electrons: 2 in its 4s subshell, and 4 inits 4p subshell.

my question is, how does one know there are 6 valence electrons?

 

[psiyung]

Bonding occurs only with the electrons in the outer most shells – called the valence electrons

Inner electrons are called the core electrons

The valence electrons are those in the outer s and p orbitals, and any unfilled d and p orbitals.

 

[captaintripps]

I think the number of valence electrons can be figured by which column the element is in. Selenium ~ column VI then 6 electrons.

 

[elz787]

thanks , both of you are right, i JUST read it!