What is the Lewis dot structure for CBr4?

Answer 1

1) First write the bonding sequence. Usually the first atom, other than H is the central atom. In this example Br is the central atom. Write Br first and draw two bonds to connect the 2 extra Br atoms in the Br3-.

Br-Br-Br

2) Count the total number of valence electrons : 3 X 7 + 1 = 22 (since bromine belongs to VII group, each Br has 7 valence electrons and add 1 for each - ve charge)

3) Since there are two bonds in the structure drawn in rule 1, subtract 4 bonding electrons (2 electrons for each bond) from the total valence electrons, 22 (22-4 =18). This gives 18 electrons.

4) Distribute these electrons to the atoms in the Br3-. First satisfy the surrounding atoms, making sure that each atom has an octet around it (H will have doublet). Each surrounding Br atom needs 6 electrons to attain octet. Place three pairs of electrons on each of the surrounding Br atom.

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:Br - Br - Br: (Note: lone pairs are not placed correctly, and I am not able to edit it)

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12 electrons (2 x 6=12) are used. Still 6 (18-6= 12) electrons are remaining from rule 3. Place them as three pairs around the central Br atom.

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:Br - Br - Br:

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In this example, the central atom Br has 10 electrons around it, in other words it exceeded the octet. Elements from the third period and below can exceed the octet since they have the d orbitals to accommodate the excess electrons.

Since this is an ionic species, draw a square bracket and show the -ve charge of the ion as superscript.

.. .. .. _

[:Br - Br - Br:]

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(Note: This editor doesn't let me put the lone pairs on the atoms correctly. I tried to edit and correct it, but goes back to the same way as given above. You please redraw it with three electron pairs around each Br with the -ve charge superscripted.)

Pushpa Padmanabhan

Lansing Community College

Answer 2

We know carbon is the central atom because it makes more bonds than the individual bromine atoms. Since carbon can promote an electron from its 2s shell to its 2p shell and then hybridize, we understand that carbon can make four bonds. Bromine is capable of single bonds, as it is a halogen that has not yet been ionized.

This is a molecular bond, so the way we draw the Lewis structure will differ from an ionic bond.

Although I cannot draw it here, the shape would be a tetrahedral, with 109.50 between each bond. This is in accordance with VSEPR, as the electrons on the central atom are separated by the greatest distance possible with four bonds.

Answer 3

Well S is the central atom and there are four Br, so the electron total is 34, Bond the Br to s and you'll have 26 electrons left, then add the e- to the Br and you'll have 2 left that you put as a lone pair on s.

Answer 4

It has 32 valence electrons, and it's tetrahedral.

Answer 5

The Lewis structure for C2H3Br is as follows: Two C atoms are double bonded together. One C atom is bonded to two H atoms and the other is bonded to an H atom and a Br atom.

Answer 6

C ___ c