Question

which determines the reactivity of an alkali metal?
its boiling and melting points
the shininess of its surface
the number of protons it has
its ability to lose electrons

Explanation:

Alkali metals are in Group 1 of the periodic table and have 1 valence - electron. Their reactivity is determined by their ease of losing this outermost electron to achieve a stable electron configuration. Boiling and melting points, shininess, and number of protons do not directly determine their chemical reactivity.

Answer:

D. its ability to lose electrons