Use the periodic table to write the electron configuration for Si. Represent the core electrons with the symbol of the previous noble gas. (i.e. short-hand notation)
The correct answer and explanation is :
Electron Configuration for Silicon (Si):
[Ne] 3s² 3p²
Explanation (300 words):
Silicon (Si) is a chemical element with atomic number 14, meaning it has 14 electrons in a neutral atom. To write its electron configuration using shorthand notation, we use the symbol of the previous noble gas to represent the core electrons—the electrons in completely filled inner shells.
The noble gas that comes before silicon in the periodic table is Neon (Ne), which has an atomic number of 10. This means the first 10 electrons of silicon have the same configuration as neon:
- 1s² 2s² 2p⁶ → total of 10 electrons (Ne)
These 10 electrons are the core electrons and are represented by [Ne] in shorthand notation.
Now, we account for the remaining 4 electrons (14 total – 10 in [Ne] = 4). These electrons go into the third energy level, specifically:
- 3s² → 2 electrons
- 3p² → 2 electrons
So, the remaining 4 electrons are arranged as 3s² 3p².
Putting it all together, the shorthand electron configuration for silicon is:
[Ne] 3s² 3p²
This notation tells us that silicon has its valence electrons (those involved in chemical bonding) in the third energy level, specifically in the s and p orbitals. These 4 valence electrons (2 in 3s and 2 in 3p) are key to silicon’s chemistry—particularly its ability to form four covalent bonds, which is fundamental to its role in semiconductors and biological systems.
Using noble gas shorthand not only saves space but also emphasizes the important valence electrons, which are primarily responsible for the chemical behavior of the element.