Noble Gas Valence Electrons

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005115864
Posts: 64
Joined: Fri Sep 28, 2018 12:15 am

Noble Gas Valence Electrons

Postby 005115864 » Sun Nov 11, 2018 10:06 pm

Hi! Can someone explain to me why in the lewis structure for XeF2 why does Xe, the central atom have 3 sets of lone pairs? I know that noble gases have a valence electron number of 8 but in this example it has 10 and while I know Xe can exceed the octet rule, how do I know to add those extra electrons and why doesn't it have a charge?

Louise Zhuang
Posts: 31
Joined: Fri Sep 28, 2018 12:28 am

Re: Noble Gas Valence Electrons

Postby Louise Zhuang » Sun Nov 11, 2018 11:32 pm

Because the VSEPR theory predicts that XeF₂ is linear, and Xe needs 3 lone pairs in order to maintain the linear structure of the molecule.

Kevin Tang 4L
Posts: 83
Joined: Fri Sep 28, 2018 12:28 am

Re: Noble Gas Valence Electrons

Postby Kevin Tang 4L » Sun Nov 18, 2018 5:24 pm

The central atom does have three lone pairs of electrons that may give the impression that it looks trigonal bipyramidal, but the angle between the two F is 180degrees, which is linear.

Pooja Sheladiya 1L
Posts: 30
Joined: Fri Sep 28, 2018 12:19 am

Re: Noble Gas Valence Electrons

Postby Pooja Sheladiya 1L » Sun Nov 18, 2018 6:08 pm

You know to add more than 8 electrins to the central atom if all the surrounding atoms already have a full octet and even after filling the octet of each atom you have extra electron left over. Most likely the extra electrons will be added to the central atom if it is in period three and can hold more than an octet.


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