Question

question 22 (1 point) saved
which of the following has the greatest number c unshared electrons around the central atom?
i3-
sf4
so2
nh3
h2o
you can use this periodic table during the quiz.
however, as stated in the course outline, and in
the orientation session, this quiz is not open book.
you cannot access course material while you write
the quiz. nor can you google your answers, work a
group, use a cheat sheet, etc.

Explanation:

• For \(I_3^-\): The central \(I\) atom has \(7\) valence electrons. It forms \(2\) single bonds (shares \(2\) electrons) and has a negative charge (adds \(1\) electron). So, the number of unshared electrons is \(\frac{7 + 1- 2}{2}=3\) pairs ( \(6\) unshared electrons).
• For \(SF_4\): The central \(S\) atom has \(6\) valence electrons. It forms \(4\) single bonds (shares \(4\) electrons). The number of unshared electrons is \(\frac{6 - 4}{2}=1\) pair ( \(2\) unshared electrons).
• For \(SO_2\): The central \(S\) atom has \(6\) valence electrons. It forms \(2\) double bonds (shares \(4\) electrons). The number of unshared electrons is \(\frac{6 - 4}{2}=1\) pair ( \(2\) unshared electrons).
• For \(NH_3\): The central \(N\) atom has \(5\) valence electrons. It forms \(3\) single bonds (shares \(3\) electrons). The number of unshared electrons is \(\frac{5 - 3}{2}=1\) pair ( \(2\) unshared electrons).
• For \(H_2O\): The central \(O\) atom has \(6\) valence electrons. It forms \(2\) single bonds (shares \(2\) electrons). The number of unshared electrons is \(\frac{6 - 2}{2}=2\) pairs ( \(4\) unshared electrons).

Answer:

\(I_3^-\)