Question

5. _______ with the largest atoms and the smallest number of valence electrons and _______ with the smallest atoms and the greatest number of valence electrons are the most reactive.

Answer 1

We have to fill the gap

The correct answer is: Metals with the largest atoms and the smallest number of valence electrons and non-metals with the smallest atoms and the greatest number of valence electrons are the most reactive.

Reactivity of any species depends on ease of release or gain of electron. The species which can release electron easily from valence shell, the species is more reactive whereas the species which can accept electron to its valence shell easily is also more reactive.

Answer 2

Explanation:

Metals are the substances that contain less number of valence electrons. Whereas as non-metals are the substances that contain more number of valence electrons.

Also, when we move down a group then there occurs increase in size of atoms due to addition of electrons.

So, outer shell of atoms move away from the nucleus. Hence, force of attraction between nucleus and valence electrons of metals decreases. So, metals are able to lose an electron easily with increase in size.

On the other hand, non-metals find it difficult to attract an electron when increase in size of atom occurs.

Thus, we can conclude that metals with the largest atoms and the smallest number of valence electrons and non-metals with the smallest atoms and the greatest number of valence electrons are the most reactive.