Question

multiple choice question
group iii elements are unreactive because
o they are relatively massive compared with other elements
o their electrons are held particularly strongly by their nucleus.
o they have complete outer energy levels
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Explanation:

Group 18 elements are noble gases. The reactivity of an element is related to its tendency to gain, lose, or share electrons. Noble gases have complete outer energy levels (valence shells). A complete valence shell makes the atom very stable. Atoms react to achieve a stable electron configuration (usually a complete valence shell). Since noble gases already have a complete outer energy level, they do not need to gain, lose, or share electrons easily, making them unreactive.

• Massiveness (\(m\)) of an atom (related to atomic mass) is not directly related to reactivity in the context of noble - gas unreactivity.
• While the nucleus does hold electrons, for noble gases, the key factor is the complete outer shell, not just the general electron - nucleus interaction in terms of strength (in the context of this question about why they are unreacted).

Answer:

they have complete outer energy levels