Question

On descending a group, electropositive character of elements:
A) increases
B) decreases
C) remains same
D) none of these

Answer 1

You must first understand what is electropositive character and how it depends on the size of the elements. Electropositive character is the tendency of an element to lose its electrons. Down the group size increases and thus, effective nuclear charge on outermost electrons decreases.

Complete step by step answer:
When an atom loses its electrons, it forms a positive ion and this is called electropositivity or electropositive character of the atom.
As we move down the group, the principal quantum number increases and the valence electrons are farther away from the nucleus. Thus we can say, effective nuclear charge decreases on descending a group which results in the decreased force of attraction of electrons to the nucleus. When electrons are less attracted towards the nucleus, they can be easily removed. Hence, an element can easily lose its electrons and form positive ions called cations. Therefore, larger the size of an atom, higher is the electropositive character. Hence, electropositive character of elements increases down the group.

Therefore, option A is the correct answer.

Note: Electropositive character decreases as we move across the period. This is because, as we move across a period, the nuclear charge increases. This causes a decrease in the atomic size because the nucleus attracts electrons towards itself. As the nuclear charge is high and size is also small, it becomes very difficult to remove the valence electrons from the valence shell. If an atom cannot lose its electrons, their electropositive character is less and hence as we move along the period electropositivity decreases.