Chemistry · D and f Block Elements
Work through this past-paper style MCQ, then read the full explanation. Practice more chemistry questions on mMCQ with adaptive practice and topic analytics.
What is the proton (atomic number) of an element that has four unpaired electrons in its ground state?
- A
6
- B
14
- C
22
- D
26
The number of unpaired electrons in an element's ground state corresponds to the element's atomic number, which is the number of protons in its nucleus. In this case, an element with four unpaired electrons would have an atomic number of 26. Iron has an atomic number of 26; it has four unpaired electrons in its ground state electronic configuration:
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁶
6: The element with atomic number 6 is carbon, which has 4 electrons in its outer shell but only 2 unpaired electrons in its ground state.
14: The element with atomic number 14 is silicon, which has 4 unpaired electrons, but it doesn’t have 4 unpaired electrons in its ground state.
22: The element with atomic number 22 is titanium, which doesn’t have 4 unpaired electrons in its ground state.
The number of unpaired electrons in an element's ground state corresponds to the element's atomic number, which is the number of protons in its nucleus. In this case, an element with four unpaired electrons would have an atomic number of 26. Iron has an atomic number of 26; it has four unpaired electrons in its ground state electronic configuration:
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁶
Tagged under Chemistry · D and f Block Elements · 2023