[Campbell Biology P.83] Based on Figure 2.7, which of the following statements about Magnes... | Practice Question

Based on Figure 2.7, which of the following statements about Magnesium Mg is correct?

  • A: Its atomic number is 11, and it has 2 electron shells.
  • B: It has 12 protons, 12 electrons, and 3 electron shells.
  • C: It has 12 protons, 10 electrons, and 2 electron shells.
  • D: It has 2 valence electrons and is located in the second shell.

Explanation

Figure 2.7 shows Magnesium Mg with an atomic number of 12. This means it has 12 protons. In a neutral atom, the number of electrons equals the number of protons, so it also has 12 electrons. The diagram places Mg in the 'Third shell' row, indicating it has 3 electron shells.