Question

Pick out the chemically most reactive elements from the given triads.
Li, Na, K F, Cl, Br
(a) Li and F
(b) Li and Br
(c) K and F
(d) K and Br

Answer 1

Answer:

option c

Explanation:

because potassium (k) and flourine (F) react with most other elements while other pair of options do not as compared to it

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Answer 2

Answer:

From the given triads, elements K and F are chemically most reactive. Option (c) is correct.

Explanation:

• The reactivity is determined by the number of electrons in the outermost shell.
• Due to full electron shells, noble gases have low reactivity.

The reactivity increases as we move down the group in a periodic table. Li, Na, and K are all group 1 metals. So, K is the most reactive as it lies below both Li and Na in the periodic table.

In Fluorine (F),  the valence electrons are closer to the nucleus compared to the Cl and Br. So, F is more reactive than Br and Cl.

Hence, from the given triads, elements K and F are chemically most reactive.

Option (c) is correct.