General Chemistry

First, we need to draw the Lewis structure of CH3+.

In short, these are the steps you need to follow for drawing a Lewis structure:

1.  Write the correct skeletal structure for the molecule.

        *   Hydrogen atoms are always terminal (only one bond)

        *   Put more electronegative elements in terminal positions

2. Sum the valence electrons from all the atoms.

3. Use a pair of electrons to form a bond between each pair of bound atoms.

4. Add the remaining electrons to satisfy the octet for a more electronegative atom first.

5. If any atoms lack an octet, make a double or triple bond to give them an octet.

The methyl cation (CH3+) has 4 + 3 – 1 = 6 valence electrons. We subtract one because there is a formal charge of 1+. All the six electrons are used to make the three C-H bonds, so we can show the Lewis structure of CH3as:

We can confirm the formal charge of carbon by using the formula:

FC= V – (N + B)


V – number of valence electrons
N – number of nonbonding electrons
B – number of bonds

So, the formal charge of the oxygen will be

FC (C) = 4 – (0 + 3) = +1

The steric number of carbon is three which corresponds to sp2 hybridization, and both electron and molecular geometries are trigonal planar.


Check this 99-question multiple-choice quiz on Geometry and Hybridization:


Geometry and Hybridization Quiz

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