Question

page 4 of 5
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 as
a group, use a cheat sheet, etc.

question 16 (1 point)
which of the following has the lowest number of
unshared electrons around the central atom?
xef₄
so₂
clf₃
h₂o
sf₆

Explanation:

Step1: Determine the central atom and its valence electrons

• For \(XeF_4\): Central atom is \(Xe\), valence electrons of \(Xe = 8\). It forms \(4\) bonds with \(F\) atoms. Using the formula \(unshared\ electrons=(valence\ electrons - number\ of\ bonds)\), \(unshared\ electrons = 8 - 4=4\) ( \(2\) pairs).
• For \(SO_2\): Central atom is \(S\), valence electrons of \(S = 6\). It forms \(2\) double - bonds (equivalent to \(2\) bonds in terms of electron - pair donation for unshared electron calculation). \(unshared\ electrons=6 - 2 = 4\) ( \(2\) pairs).
• For \(ClF_3\): Central atom is \(Cl\), valence electrons of \(Cl=7\). It forms \(3\) bonds with \(F\) atoms. \(unshared\ electrons = 7 - 3=4\) ( \(2\) pairs).
• For \(H_2O\): Central atom is \(O\), valence electrons of \(O = 6\). It forms \(2\) bonds with \(H\) atoms. \(unshared\ electrons=6 - 2 = 4\) ( \(2\) pairs).
• For \(SF_6\): Central atom is \(S\), valence electrons of \(S = 6\). It forms \(6\) bonds with \(F\) atoms. \(unshared\ electrons=6 - 6=0\).

Answer:

\(SF_6\)