Question

of these nonmetals, which one is likely to be the least reactive? oxygen (o) sulfur (s) chlorine (cl) fluorine (f)

Explanation:

Step1: Recall Reactivity Trends

In the periodic table, for nonmetals, reactivity generally increases as we move up a group (due to smaller atomic size, stronger attraction for electrons) and across a period (from left to right, for nonmetals, towards higher electronegativity).

Step2: Analyze the Elements' Positions

• Oxygen (O) is in Group 16, Period 2.
• Sulfur (S) is in Group 16, Period 3.
• Chlorine (Cl) is in Group 17, Period 3.
• Fluorine (F) is in Group 17, Period 2.

For Group 16, as we move down the group (from O to S), atomic size increases, and the ability to gain electrons (reactivity) decreases. For Group 17, F (Period 2) is more reactive than Cl (Period 3). Comparing S (Group 16, Period 3) with O (Group 16, Period 2), S is less reactive than O. Comparing S with Cl: Cl is in a more reactive group (17) and same period (3), but Cl is more reactive as it needs 1 electron, S needs 2, but the group trend for nonmetals (reactivity up group) makes S (Group 16, Period 3) less reactive than Cl (Group 17, Period 3), and also less reactive than O (Group 16, Period 2) and F (Group 17, Period 2). So sulfur (S) is the least reactive among these.

Answer:

B. sulfur (S)