Question

a chemist made the table below to record some atomic properties of four elements. based on the information in the table, which conclusion about the chemical reactivity of these elements is valid? a krypton is the least reactive because it has 8 electrons in the outer shell. b beryllium is the most reactive because it has 2 electrons in the outer shell. c sulfur is the most reactive because it has the same number of electrons, protons, and neutrons. d oxygen is the least reactive because it the same number of protons and neutrons.

Explanation:

• For noble gases (like Krypton), having a full outer shell (8 electrons) makes them very stable and unreactive.
• Beryllium (Be) has 2 outer - shell electrons but is not the most reactive as its reactivity is influenced by its position in the periodic table (it's a metal in group 2, but not as reactive as alkali metals).
• Sulfur (S) having equal numbers of electrons, protons, and neutrons (\(16 = 16=16\)) is about its atomic composition, not reactivity. Reactivity of non - metals like S is more related to its tendency to gain electrons (it has 6 outer - shell electrons and wants to gain 2).
• Oxygen (O) having equal protons and neutrons (\(8 = 8\)) is about its atomic composition. Oxygen has 6 outer - shell electrons and is reactive (tends to gain 2 electrons).

Answer:

A. Krypton is the least reactive because it has 8 electrons in the outer shell.