Competency #6

Answer and Explanation

The correct answer is A.

Which of the following statements best describes the ionic bond between magnesium and oxygen?

  1. Magnesium will give away 2 electrons and oxygen will gain 2 electrons, and the resulting ions will be attracted to each other. This is the correct answer. The question asks about ionic bonding, but the Bohr models shown in the problem statement are for neutral atoms (magnesium has 12 protons and 12 electrons, while oxygen has 8 protons and 8 electrons). We can see that magnesium could lose 2 electrons to have a full outer shell, while oxygen must gain 2 electrons to have a full outer shell. Thus magnesium will form a Mg2+ ion, while oxygen will form an O2- ion. Opposites attract; thus these oppositely charged ions are drawn together. This attraction is called ionic bonding.
  2. The outer electron shells of magnesium and chlorine will overlap. The overlap of outer electron shells is a characteristic of covalent bonding.
  3. Oxygen will give 6 electrons to magnesium. With 6 electrons in its outer shell, oxygen tends to gain 2 electrons rather than losing 6 electrons as its means to obtaining a full outer shell.
  4. None of the above.
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