Answer
$EO_3^-$
Work Step by Step
For the given Lewis structure, where E is an unknown element, some possible identities for element E could be:
$EO_3^-$
The Lewis structure has 26 valence electrons. If $x$ is number of valence electrons of element E. We determine $x$:
$26 = x + 3(6) + 1$
$x = 7$ valence electrons
Element E is a halogen because halogens have seven valence electrons. Some possible
identities are
$F, Cl, Br$ and $I$.
The $EO_3^-$ ion has a trigonal pyramid molecular structure with
bond angles of less than 109.5° (<109.5°).
