Ask Question
3 June, 05:17

Calcium (atomic number 20) has electron configuration 1s2,2s2,2p6,3s2,3p6,4s2. The atomic number of scandium is 21. Which orbital does the 21st electron enter?

a. 3d b. 4p c. 4d d. 4f

+3
Answers (1)
  1. 3 June, 08:40
    0
    a. 3d

    The electrons in an atom fill the shells in order from least energy to higher energy. The orbitals from lowest to highest are

    1s - 1 orbital, 2 electrons

    2s - 1 orbital, 2 electrons

    2p - 3 orbitals, 6 electrons

    3s - 1 orbital, 2 electrons

    3p - 3 orbitals, 6 electrons.

    4s - 1 orbital, 2 electrons. Note the energy for the 4s orbital is just barely

    lower than the 3d orbitals. So it fills up before the 3d orbitals.

    3d - 5 orbitals, 10 electrons.

    Since the 20th electron fills the 4s shell, the 21st electron goes into the next higher energy orbital which is one of the 3d orbitals.
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Calcium (atomic number 20) has electron configuration 1s2,2s2,2p6,3s2,3p6,4s2. The atomic number of scandium is 21. Which orbital does the ...” in 📙 Chemistry if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers