CH3Br (Methyl Bromide | Bromomethane) Lewis Structure and Steps of Drawing

Methyl bromide (CH3Br or bromoethane) is an alkyl halide compound. It has only one carbon atom. Lewis structure of CH3Br contains 3 C-H bonds and 1 C-Br bond. Carbon atom is the center atom and bromine atom has 3 lone pairs. We will learn how to draw lewis structure of CH3Br step by step in this tutorial.

CH3Br lewis structure

CH3Br lewis structure

Figure of CH3Br lewis structure is given above and you can see how atoms are joint with other atoms. Also, there are no charges on atoms and CH3Br also does not have an overall charge.

Methyl bromide | bromomethane | CH3Br

An organobromine compound which exist as a nonflammable gas at room temperature. It is an ozone-depleting compound with one bromine atom. Methyl bromide is an acute toxic chemical and should carefully handle with proper safety equipments.

Steps of drawing lewis structure of CH3Br

There are several steps to draw the lewis structure of CH3Br. Each step is explained in detail in this tutorial.

  1. Find total number of electrons of the valance shells of hydrogen, oxygen atoms and carbon atom
  2. Determine total electrons pairs as lone pairs and bonds
  3. Find center atom and basic sketch
  4. Mark lone pairs on atoms
  5. Mark charges on atoms if there are charges.
  6. Check the stability and minimize charges on atoms by converting lone pairs to bonds to obtain best lewis structure.

Total number of electrons of the valance shells of CH3Br

There are 3 elements in CH3Br molecule; hydrogen, carbon and bromine. Hydrogen is a group IA element and has only 1 electron in its valence shell. Bromine is a group VIIA element in the periodic table and contains 7 electrons in its last shell. Carbon atom has 4 electrons in its last shell because it is a IV group element. Now we know how many electrons are includes in valence shells of atoms.

  • valence electrons given by hydrogen atoms = 1 * 3 = 3
  • valence electrons given by carbon atom = 4 * 1 = 4
  • valence electrons given by bromine atom = 7 * 1 = 12

  • Total valence electrons = 3 + 4 + 7 = 14

Total valence electrons pairs

Total valance electrons pairs = σ bonds + π bonds + lone pairs at valence shells

Total electron pairs are determined by dividing the number total valence electrons by two. For, CH3Br, total pairs of electrons are 7 (14/2) in their valence shells.

Center atom and basic sketch of CH3Br

To be the center atom, ability of having greater valance and being most electropositive element in the molecule are important facts. These are not essential. But those two facts play a major role in selecting center atom of a molecule.

However, CH3Br is a simple molecule. Carbon atom has the more chance to be the center atom than hydrogen and bromine atoms.

CH3Br bromomethane basic sketch

Lone pairs on atoms

After deciding the center atom and sketch of CH3Br molecule, we mark lone pairs on atoms. Remember that, there are total of 7 electron pairs to mark on atoms as bonds and lone pairs.

  • There are already 4 bonds in the above drawn sketch. Now only 3 (7-4) electron pairs are remaining to mark on atoms.
  • Usually, those remaining electron pairs should be started to mark on outside atoms. But, hydrogen atoms cannot keep more than two electron in its last shell and there is no possibility mark lone pairs on hydrogen atoms.
  • Therefore, then mark those electrons pairs on bromine atom; Bromine atom will take all remaining 3 lone pairs.
mark lone pairs on atom in CH3Br bromomethane

Mark charges on atoms and check the stability and minimize charges on atoms by converting lone pairs to bonds

There are no charges on atoms and we do not need to the step of reducing charges of atoms.


CH3Br lewis structure molecular geometry

There are three single bonds between carbon atom and three hydrogen atoms. As well, there is a one carbon-bromine atom. Finally, there are four sigma bonds around the center atom, carbon. Therefore, molecular geometry and shape of CH3Br molecule is tetrahedral.

CH3Br valence electrons?

Each hydrogen atom give one electrons to make single bonds with carbon atom. Carbon gives its all four electrons to make bonds with hydrogen and bromine atom. But, bromine only gives one electron to make a bond with carbon atom.

How many lone pairs are there in bromoethane?

Only bromine atom has lone pairs. Bromine has three lone pairs in bromoethane.

Similar lewis structures to methyl bromide molecule