Question

complete the table to describe the properties of each set of elements.
elements metals or nonmetals? reactive or unreactive?
br, cl, f
k, rb, na
ar, kr, xe

Explanation:

Step1: Identify Br, Cl, F

Bromine (Br), chlorine (Cl) and fluorine (F) are halogens, which are non - metals. They are very reactive as they need to gain one electron to achieve a stable octet configuration.

Step2: Identify K, Rb, Na

Potassium (K), rubidium (Rb) and sodium (Na) are alkali metals. They are highly reactive because they have one valence electron which they readily lose to achieve a stable electron configuration.

Step3: Identify Ar, Kr, Xe

Argon (Ar), krypton (Kr) and xenon (Xe) are noble gases. They have full outer electron shells, so they are unreactive.

Answer:

Elements	Metals or non - metals?	Reactive or unreactive?
K, Rb, Na	Metals	Reactive
Ar, Kr, Xe	Non - metals	Unreactive