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. Their reactivity is based on their tendency to lose the single electron in their outermost shell (valence electron). When they lose this electron, they form a +1 ion. Boiling/melting points relate to physical properties, shininess is a physical characteristic (metallic luster), and the number of protons determines the element's identity (atomic number), not reactivity. Reactivity in metals (like alkali metals) often depends on how easily they can lose electrons (oxidation).

Answer:

its ability to lose electrons