Question

which element is the most reactive?
o sodium
o nickel
o carbon
o oxygen

Explanation:

Sodium is an alkali - metal. Alkali - metals are highly reactive as they have one valence electron and readily lose it to achieve a stable electron configuration. Nickel is a transition metal with relatively lower reactivity. Carbon is a non - metal and its reactivity depends on the context but is generally less reactive than alkali metals. Oxygen is reactive but not as reactive as sodium under standard conditions.

Answer:

sodium