Identify the correct Lewis structure  of CH3− . Ensure that all charges and lone pairs are shown.

1. Start by identifying the total number of valence electrons. Carbon (C) has 4 valence electrons, each Hydrogen (H) atom has 1 valence electron, and the extra electron from the negative charge gives us a total of 4 + (3*1) + 1 = 8 valence electrons.

2. Draw a skeleton structure of the molecule. Carbon is less electronegative than hydrogen, so it is the central atom, surrounded by the three hydrogen atoms.

3. Distribute the valence electrons among the atoms. Each bond (line) represents 2 electrons, and each atom should have an octet (8 electrons) except for hydrogen, which should only have 2 electrons.

4. The Lewis structure for CH3- would look like this:

   H | H-C-H :

The lines between C and H represent bonds (2 electrons), and the pair of dots (:) represent the lone pair of electrons on the carbon atom. The negative charge is indicated by the minus sign, which shows that there is an extra electron in the structure.