Question

the overall charge is -1 for the lewis structure shown below. choose the possible identity or identities of the central atom.

Explanation:

Let's analyze each option:

• Option A (F): Fluorine typically forms only one bond (as it has 7 valence electrons and needs one more to complete its octet). In the given Lewis structure, the central atom forms three bonds, so F cannot be the central atom.
• Option B (N, P, or As): These elements (group 15) have 5 valence electrons. If the central atom is N, P, or As, and there is an overall charge of - 1. Let's assume the general formula \(XO_{3}^{-}\) (where \(X = N, P, As\)). Using the formula for formal charge \(FC=V-\frac{N}{2}-B\) (where \(V\) is the number of valence electrons, \(N\) is the number of non - bonding electrons, and \(B\) is the number of bonding electrons). For \(NO_{3}^{-}\), \(V = 5\), \(N=2\) (lone pair on N), \(B = 6\) (three double - bond equivalents in resonance structures, but in a simple Lewis structure with single bonds and a charge). The formal charge of \(N\) in \(NO_{3}^{-}\) is \(5-\frac{2}{2}-6=-2\), but considering resonance and the overall charge of the ion, these elements can be in such a structure.
• Option C (C, Si, or Ge): Group 14 elements have 4 valence electrons. If they form three bonds (as in the structure), they would have a formal charge that is not consistent with the overall - 1 charge of the ion. For example, for \(CO_{3}^{2 -}\), the charge is - 2 (not - 1 as required here).
• Option D (B or Al): Group 13 elements have 3 valence electrons. If they form three bonds, they would have a formal charge that is not consistent with the overall - 1 charge of the ion.
• Option E (Cl, Br, or I): Group 17 elements have 7 valence electrons. If they form three bonds, the formal charge and electron - pair geometry do not match well with the overall - 1 charge and the structure (they usually form odd - numbered bonds like \(ClO_{4}^{-}\) with more bonds).

Answer:

B. N, P, or As