Question

The molecule having the smallest bond angle is:
A.$NC{l_3}$
B.$AsC{l_3}$
C.$SbC{l_3}$
D.$PC{l_3}$

Answer 1

This question gives the knowledge about periodic table and electronegativity. Periodic table is basically the tabular representation of elements, which are organized by electronic configuration, atomic number and repeated chemical properties.

Complete answer:
In the periodic table, as we go down the group the bond angle of the elements decreases gradually. Also, the bond angle is based on the factor of electronegativity. Electronegativity is the potential of an atom to fascinate a shared pair of electrons towards itself. And it is clearly evident that with the decrease in electronegativity of elements the bond angle also decreases. The electronegativity of $SbC{l_3}$ is least. So, the bond angle of $SbC{l_3}$ will also be smaller.

Therefore, option $C$ is the correct option.

Additional information:
Periodic table is basically the tabular representation of elements, which are organized by electronic configuration, atomic number and repeated chemical properties. Periodic table consists of seven rows and eighteen groups. In rows, the elements are organized from left to right and in groups, elements are organized from top to bottom. In total there are $118$ elements present in the periodic table.
Properties of periodic table are as follows:
$1$. The elements which are present in the same group experience the same electronic configuration in the valence shell.
$2$. The elements which are present in the same group experience similar chemical properties.
$3$. The elements which are present in the same period experiences increase in valence electrons.
$4$. The elements which are present in the same period experiences increase in the number of energy subshells.
$5$. In the periodic table, ionization energy decreases the group.
$6$. In the periodic table, electronegativity decreases the group.
$7$. In the periodic table, atomic radii increases the group.

Note:
Always remember the concept that the periodic table is the representation of elements, organized by electronic configuration, atomic number and repeated chemical properties. Electronegativity is the potential of an atom to fascinate a shared pair of electrons towards itself.