Valence Electrons from Periodic Table

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rachelle1K
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Joined: Sat Sep 07, 2019 12:16 am

Valence Electrons from Periodic Table

Postby rachelle1K » Wed Oct 30, 2019 4:17 pm

How do you tell the number of valence electrons by just looking at the periodic table?

Cooper Baddley 1F
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Re: Valence Electrons from Periodic Table

Postby Cooper Baddley 1F » Wed Oct 30, 2019 4:25 pm

The number of valence electrons for an element is equal to its group number starting at one on the left and moving to eight on the far right.

Astrid Lunde 1I
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Re: Valence Electrons from Periodic Table

Postby Astrid Lunde 1I » Wed Oct 30, 2019 5:00 pm

To find the valence electron from the periodic table look at the group number.

KnarGeghamyan1B
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Re: Valence Electrons from Periodic Table

Postby KnarGeghamyan1B » Wed Oct 30, 2019 5:10 pm

It does correspond to the group but make sure you skip over the transition metals in the middle when looking at elements toward the right. For example, Boron has 3 valence electrons, not 13.

Ellis Song 4I
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Re: Valence Electrons from Periodic Table

Postby Ellis Song 4I » Wed Oct 30, 2019 6:12 pm

The number of valence electrons is determined by the group number. For groups 13-18, the number of valence electrons is the number in the ones place.

BCaballero_4F
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Re: Valence Electrons from Periodic Table

Postby BCaballero_4F » Wed Oct 30, 2019 6:27 pm

You get the number of valence electrons from whatever group the element is in.

Jessica Li 4F
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Re: Valence Electrons from Periodic Table

Postby Jessica Li 4F » Wed Oct 30, 2019 6:33 pm

I think it's helpful if you have time to write down the electron configuration. Then, you can just count all the subscripts in the highest n level and add them up. This helps prevent confusion with the d orbitals. For instance, for Zinc, the config would be 1s2 2s2 2p6 3s2 3p6 3d10 4s2. Since n =4 is the highest level, and there are only two in the 4s shell, zinc has 2 valence electrons.

Kristina Rizo 2K
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Re: Valence Electrons from Periodic Table

Postby Kristina Rizo 2K » Thu Oct 31, 2019 1:31 pm

505258921 wrote:It does correspond to the group but make sure you skip over the transition metals in the middle when looking at elements toward the right. For example, Boron has 3 valence electrons, not 13.

So we normally skip over the d-block unless stated otherwise? For example, hw problem 2A.1a asks to give the number of valence electrons (including d electrons) for the element Sb. Since it asked to include d-block, the answer would be 15 valence electrons not 5 electrons correct?

MinuChoi
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Joined: Wed Sep 18, 2019 12:15 am

Re: Valence Electrons from Periodic Table

Postby MinuChoi » Thu Oct 31, 2019 3:00 pm

For example, hw problem 2A.1a asks to give the number of valence electrons (including d electrons) for the element Sb. Since it asked to include d-block, the answer would be 15 valence electrons not 5 electrons correct?


The valence electrons for Sb would be 5. Keep in mind that the d-block (4d) that is completely full is not in the highest shell (5s25p3). This is why you skip over the transition metal groups when counting nonmetal groups for valence electrons.

Merin Padayatty 3G
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Re: Valence Electrons from Periodic Table

Postby Merin Padayatty 3G » Sat Nov 02, 2019 10:43 am

The number of valence electrons is determined by the group number.

Leyna Dang 2H
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Joined: Thu Jul 25, 2019 12:17 am

Re: Valence Electrons from Periodic Table

Postby Leyna Dang 2H » Sat Nov 02, 2019 12:05 pm

You can look at the group numbers on the periodic table, but this doesn’t apply to d-block elements. For groups 13-18, the valence electrons correspond to the number that is in the ones place. So oxygen, for instance, is in group 16 so it would have 6 valence electrons.


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