Question

On moving down the group from F to I, which of the properties decreases? (This question has multiple correct answers.)
(a)- Ionic radius
(b)- Ionization energy
(c)- Oxidizing agent
(d)- Electronegativity

Answer 1

Hint: Fluorine, chlorine, bromine, and iodine are the elements of group 17. The size of the atom increases down the group, the nuclear charge decreases, and the tendency to lose electrons down the group increases.

Complete answer:
Let us study the options one by one:
(a)- Ionic radius: Halogens have the smallest atomic radii in their respective periods. This is due to the reason that atom radii decreases as the nuclear charge increases as we move along the period. But both the atomic and ionic radii increase from fluorine to iodine as the number of shells increase.
Hence this option is incorrect.
(b)- Ionization energy: The ionization energy of the halogens is very high. This implies that halogens have very little tendency to lose electrons. The ionization energy decreases as the size of the halogen increases down from F to I.
Hence, this option is correct.
(c)- Oxidizing agent: Since all the halogens have a strong tendency to accept an electron, they act as strong oxidizing agents. However, their oxidizing power decreases from fluorine to iodine.
Hence, this is the correct option.
(d)- Electronegativity: Due to small size and higher nuclear charge, each halogen has the highest electronegativity in its period. As we move down the group from fluorine to iodine, electronegativity decreases due to corresponding increases in the size of the atom.
Hence, this option is correct.
So, the correct answer is “Option B,C and D”.

Note: Since the oxidizing power decreases down the group, fluorine is the strongest oxidizing agent among all. It can oxidize every element. Iodine in the group is the strongest reducing agent.