Write the Lewis dot structural formula for each of the following. Give also, the formula of a neutral molecule, which has the same geometry and the same arrangement of the bonding electrons as in each of the following. An example is given below in the case of `H_(3)O^(+) and NH_(3)`.
`underset("structure")underset("Lewis dot")([H:underset(* *)overset(H)overset(* *)O:H]^(+)) underset("structure") underset("Neutral")([H:underset(* *)overset(H)overset(* *)N:H])`

Options

A. `O_(2)^(2-)`
B. `CO_(3)^(2-)`
C. `CN^(-)`
D. `NCS^(-)`

Explanation

To solve the problem of writing the Lewis dot structural formula for the given ions and identifying their corresponding neutral molecules, we will follow a systematic approach for each ion.

### Step 1: O2^2− (Oxide Ion)
1. **Count the total valence electrons**: Each oxygen has 6 valence electrons. For two oxygen atoms, that’s 6 + 6 = 12. Additionally, there are 2 extra electrons due to the 2− charge. So, total = 12 + 2 = 14 electrons.
2. **Draw the structure**: Place the two oxygen atoms next to each other. Use one pair of electrons to form a bond between them.
3. **Complete the octets**: Each oxygen needs 8 electrons to complete its octet. Distribute the remaining electrons to achieve this. The final structure will show a double bond between the two oxygens.
4. **Identify the neutral molecule**: The neutral molecule with the same geometry and bonding arrangement is F2 (Fluorine), which also has 7 valence electrons each.

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