Question

question 3. which of the following statements explains why potassium (k) is more reactive than sodium (na)?
potassium has more protons in its nucleus, making it more reactive.
potassiums outermost electron is farther from the nucleus, making it easier to lose.
sodium has fewer electrons, making it less reactive.
potassium is closer to the noble gases, making it more stable.

Explanation:

• Analyze Option 1: Protons affect nuclear charge, but reactivity of alkali metals (K, Na) relates to electron loss. More protons increase nuclear pull, but K is more reactive, so this is wrong.
• Analyze Option 2: K is below Na in Group 1. Atomic radius increases down the group, so K's outermost electron is farther from the nucleus. Less nuclear attraction means it's easier to lose, increasing reactivity. This matches the reactivity trend.
• Analyze Option 3: Reactivity of alkali metals depends on losing the outermost electron, not total electron count. Na has 11 electrons, K has 19; the key is electron distance from nucleus, not count. So this is incorrect.
• Analyze Option 4: Noble gases are stable. K is in Group 1, far from noble gases (Group 18). Being closer to noble gases would mean more stability (like halogens closer to noble gases are reactive, but K is in Group 1, so this is wrong as K is less stable and more reactive.

Answer:

B. Potassium's outermost electron is farther from the nucleus, making it easier to lose.