Question

Which lewis electron-dot diagram correctly represents a hydroxide ion

Answer 1

Complete Question is attached below,

Answer:
            Option-A is the correct answer.

Explanation:
                   As we know Hydroxide contains one hydrogen and one oxygen atom. Also one negative charge is being carried bu hydroxide ion as,,,

                                                       OH⁻

Now in order to draw its lewis structure we first of all calculate the total number of valence electrons of both elements i.e.

Valence electrons in Oxygen      =   6

valence electrons in Hydrogen   =   1

Number of negative charges      =   1
                                                     ------------
Total valence electrons                    8

Now, we draw both elements and connect them via a single bond and subtract 2 electrons per single bond,

                                                 =  8  -  2

                                                 =  6

Now these six electrons are added to oxygen atom as it is more electronegative element. Hence, a structure shown in Option-A is formed, and the negative charge is in fact the -1 formal charge of oxygen atom.