What is the Lewis structure for CH3Br?

The Lewis structure for CH₃Br (bromomethane) represents the arrangement of electrons around the atoms in the molecule.

To draw the Lewis structure, follow these steps:

1. Count the total number of valence electrons: Carbon (C) has 4 valence electrons, each of the three hydrogen (H) atoms has 1 valence electron, and bromine (Br) has 7 valence electrons. Therefore, the total is 4 + (3 × 1) + 7 = 10 valence electrons.
2. Determine the central atom: Carbon is the central atom because it can form four bonds and is less electronegative than bromine.
3. Connect the atoms with single bonds: Attach three hydrogen atoms to the carbon atom with single bonds, and then connect the carbon atom to the bromine atom with another single bond.
4. Distribute the remaining electrons: After forming the bonds, we’ve used 8 of the 10 available electrons (three C-H bonds and one C-Br bond). Therefore, we have 2 electrons left which can be placed as a lone pair on bromine.

The final Lewis structure looks like this:

   H   H  H
    |   |  |
    C - Br
 

In this structure:

• Carbon is surrounded by four bonds (three to H and one to Br) and has a full valence shell.
• Each hydrogen atom has a full shell (2 electrons) through their bond with carbon.
• Bromine has a full octet, as it has 6 electrons in addition to the 2 it shares with carbon (forming one bond).

This representation allows us to visualize how the atoms are connected in CH₃Br and how many electrons each atom possesses.