Question

Chemically Zinc group elements closely resemble _______ .
A. I A group
B. II A group
C. III A group
D. IV A group

Answer 1

The chemical properties of an element depend on the electronic structure of the element. The electronic arrangement of elements decides the nature of chemical reactions.

Complete step by step answer:
Zinc is an element in the periodic table with atomic number $30$. It is a transition metal. Its electronic configuration is $\left[ {Ar} \right]3{d^{10}}4{s^2}$.
Thus element Zinc has a completely filled d-orbital with $10$ electrons and a completely filled s-orbital with $2$ electrons. Hence it will resemble the properties of the other element in the periodic table which have similar completely filled shells.
Let us check the electronic arrangement of the electrons in the given set of groups of the periodic table.
- I A group. The I A group in the periodic table is also known as group $1$. It belongs to the alkali metal group. The elements in this group are hydrogen, lithium, sodium, potassium, rubidium, cesium and francium. These elements have a single electron in their outermost shell. The electron is placed in the s-orbital. Like for sodium the electronic configuration is $\left[ {Ne} \right]3{s^1}$. So it is different to that of zinc which has completely filled orbitals.
- II A group. The II A group in the periodic table is also known as group $2$. It belongs to the alkaline earth metal group. The elements in this group are beryllium, magnesium, calcium, strontium, barium, and radium. These elements have completely filled s-orbital with a pair of electrons in their outermost shell. Like for magnesium the electronic configuration is $\left[ {Ne} \right]3{s^2}$. So it is similar to that of zinc which has completely filled orbitals.
- III A group. The III A group in the periodic table is also known as group $13$. It belongs to the boron group. The elements in this group are boron, aluminum, gallium, indium, and thallium. These elements have three electrons in their outermost shell. The electrons are placed in the s-orbital (two electrons) and in p orbital (one electron). Like for aluminium the electronic configuration is $\left[ {Ne} \right]3{s^2}3{p^1}$. So it is different to that of zinc which has completely filled orbitals.
-IV A group. The IV A group in the periodic table is also known as group $14$. It belongs to the carbon group. The elements in this group are carbon, silicon, germanium, tin and lead. These elements have four electrons in their outermost shell. The electrons are placed in the s-orbital (two electrons) and in p orbital (two electrons). Like for silicon the electronic configuration is $\left[ {Ne} \right]3{s^2}3{p^2}$ . So it is different to that of zinc which has completely filled orbitals.
Hence, chemically Zinc group elements closely resemble to II A group,

Note: The reactivity of zinc metal is close to magnesium metal. It is a strong reducing agent. The reactivity of zinc favors a $+ 2$ oxidation state just like magnesium. It reacts readily with acid, alkali and other metals.