Question

A valid Lewis structure cannot be drawn for which of the following compounds?
$(P=15,Si=14,C=6,Se=34)$

• A. $P{O}_4^{3-}$
• B. $Si{F}_4$
• C. $C{F}_4$
• D. $Se{F}_4$

Answer 1

Answer: (A), (D)

$Se{F}_4$

$\left(a\right)$ Central atom, $P$ has 10 valence electrons.

$\left(b\right)$ Central atom, $Si$ has 8 valence electrons.

$\left(c\right)$ Central atom, $C$ has 8 valence electrons.

$\left(d\right)$ Central atom, $Se$ has 10 valence electrons.

Hence, $P{O}_4^{3-}$ and $Se{F}_4$ violate the octet rule.