Help on 3.49

[Amanda Cardenas 1J]

Need help on part d of 3.49. Specifically the formal charge.
3.49: Draw the lewis structure and determine the formal charge on each atom in
d) C2^2-

[Alicia Yu 1A]

The formal charge on the carbons is both 01
There is a triple bond between C and C, with one lone pair on each. Carbon's Valence is 4, so 4-5 (the number of bonds&valence)=-1

[chemlover]

Once you draw the Lewis Structure you can use the formula for formal charge! (4-5)=-1