Answer: Option (A) is the correct answer.
Explanation:
It is known that elements present in the same group tend to show similar chemical properties because they have same number of valence electrons.
Lithium and sodium are both group 1 elements and each of them have 1 valence electron. Hence, they show similar chemical properties.
Beryllium is a group 2 element and boron is a group 13 element. Hence, they do not show any similar chemical properties.
Carbon is a group 14 element and sulfur is a group 16 element. Hence, they do not show any similar chemical properties.
Hydrogen has only one electron and helium is a noble gas as it has only 2 electrons. Hence, they do not show any similar chemical properties.
Hydrogen shows the properties of both metals and non-metals. Whereas lithium being a metal will show the properties of metals only. Hence, they do not show any similar chemical properties.
Thus, we can conclude that out of the given options lithium and sodium is the pair of elements show similarities in the pattern of chemical bonding.
