F, Cl, and Br are three elements with 7 valence electrons. which has the largest atomic radius and most reactive element, respectively, among the three elements?

Explanation:

• Atomic Radius: Atomic radius increases as you move down a group in the periodic table due to the addition of electron shells. Among fluorine (F), chlorine (Cl), and bromine (Br), bromine has the largest atomic radius because it is located below chlorine and fluorine in Group 17, resulting in more electron shells and a larger atomic size.
• Reactivity: Reactivity in halogens decreases down the group. Fluorine is the most reactive because it has the smallest atomic radius, leading to a stronger attraction for electrons and a higher tendency to gain an electron to achieve a stable octet. This increased reactivity is due to fluorine's high electronegativity and effective nuclear charge.

Therefore, among the given options, bromine (Br) has the largest atomic radius, and fluorine (F) is the most reactive element.

The correct answer is a) Br and F.