What element is the electron configuration representing?
1s2 2s2 2p6 3s2 3p6 4s2.
The Correct Answer and Explanation is:
The electron configuration (1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2) represents the element calcium (Ca), which has an atomic number of 20.
Explanation
To understand this electron configuration, we need to analyze it in terms of its components. Electron configurations describe the distribution of electrons in an atom’s orbitals, following the principles of quantum mechanics. Each term in the configuration denotes the number of electrons in the respective subshells:
- 1s²: This indicates that there are 2 electrons in the first energy level (n=1) within the s subshell.
- 2s²: Similarly, this means there are 2 electrons in the second energy level (n=2) s subshell.
- 2p⁶: The p subshell in the second energy level holds 6 electrons, filling it completely. The p subshell can hold a maximum of 6 electrons.
- 3s²: Again, there are 2 electrons in the third energy level s subshell.
- 3p⁶: The p subshell in the third energy level also contains 6 electrons, completing this level.
- 4s²: Finally, this indicates that there are 2 electrons in the fourth energy level s subshell.
The atomic number of an element corresponds to the total number of protons in its nucleus, which is also equal to the total number of electrons in a neutral atom. For calcium, the total number of electrons can be calculated as follows:
[
2 \, (1s) + 2 \, (2s) + 6 \, (2p) + 2 \, (3s) + 6 \, (3p) + 2 \, (4s) = 20 \, \text{electrons}
]
Since the atomic number of calcium is 20, this configuration confirms that it is indeed calcium. Calcium is an alkaline earth metal found in group 2 of the periodic table. It is crucial for various biological processes, including bone formation and cellular signaling. The two electrons in the outermost shell (4s²) make calcium reactive, as it tends to lose these electrons to achieve a stable electron configuration similar to that of noble gases.