valence electrons

[joonkimdds]

why do we not count electrons in d subshell?

i've never thought about it when i draw the energy level and draw the electrons.

I know that oxygen(16electrons) has 2-8-6 electrons so there are 6 valence elctrons.

but what about As(33electrons)?
do i draw it so it can have 2-8-8-(skip 10 electrons from d subshell)-5 and make it have 5 valence electrons?

it seems that most of the examples from the book and study guide doesn't go to the element that has more than Ar(18proton) so i don't know how to draw the ones that go beyond 3d subshell. I believe that drawing 10 electrons from d subshall can ruin the octet rule but i don't know the reason why we should ignore them and still count them to use hund's rule and etc.

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[Moni Ahmadian]

Hi,

The right hand side of the periodic table is called the p block in which all the atoms fill in their p orbitals the left hand side is s block. Only the transition metals fill their d orbital and some of them their f orbitals. For all the representatives the d and f orbitals are filled completely prior to the valence shell and interestingly for the representatives the group number tells you the number of the electrons in the last shell so oxygen is group six and it has six electron 2 in the s and 4 in the p orbitals of the last shell!

Hope it helps

why do we not count electrons in d subshell?

i've never thought about it when i draw the energy level and draw the electrons.

I know that oxygen(16electrons) has 2-8-6 electrons so there are 6 valence elctrons.

but what about As(33electrons)?
do i draw it so it can have 2-8-8-(skip 10 electrons from d subshell)-5 and make it have 5 valence electrons?

it seems that most of the examples from the book and study guide doesn't go to the element that has more than Ar(18proton) so i don't know how to draw the ones that go beyond 3d subshell. I believe that drawing 10 electrons from d subshall can ruin the octet rule but i don't know the reason why we should ignore them and still count them to use hund's rule and etc.

 

[Streetwolf]

The order of shell filling:

1s
2s 2p
3s 3p
4s 3d 4p
5s 4d 5p
6s 4f 5d 6p
7s 5f 6d 7p

etc

So in any given period only the s and p shells contribute to the electrons in the outermost level. All the other shells are on the inside somewhere and don't contribute towards the valence electron #.

 

[jackbauer!]

The order of shell filling:

1s
2s 2p
3s 3p
4s 3d 4p
5s 4d 5p
6s 4f 5d 6p
7s 5f 6d 7p

etc

So in any given period only the s and p shells contribute to the electrons in the outermost level. All the other shells are on the inside somewhere and don't contribute towards the valence electron #.

NOTE the exceptions to the octet rule!!...one of them being that it is possible that there are more than 8 valence electrons. these electrons will occupy the d subshell. also note that this exception only occurs for elements that are in period 4 or lower.

jb!

 

[Streetwolf]

NOTE the exceptions to the octet rule!!...one of them being that it is possible that there are more than 8 valence electrons. these electrons will occupy the d subshell. also note that this exception only occurs for elements that are in period 4 or lower.

jb!

Well only if needed. In general I believe valence # is 0-7 (or 1-8 w/e).