Question

    The atom of an element contains 2 electrons in its

    M-shell. The element is:
    A Aluminium Correct Answer Incorrect Answer
    B Sodium Correct Answer Incorrect Answer
    C Chlorine Correct Answer Incorrect Answer
    D Magnesium Correct Answer Incorrect Answer

    Solution

    The electronic configuration of magnesium is 2,8,2. The M-shell (third shell) contains 2 electrons, which corresponds to magnesium (Mg, atomic number 12).

    • Sodium (Na,2,8,1) has 1 electron in its M-shell.
    • Aluminium (Al,2,8,3) has 3 electrons in its M-shell.
    • Chlorine (Cl,2,8,7) has 7 electrons in its M-shell.

    Practice Next