Give the ground-state electron configuration for silicon (Si) using noble-gas shorthand.
Give the ground-state electron configuration for silicon (Si) using noble-gas shorthand.
Express your answer in condensed form as a series of orbitals. (For example, [Ar]4s23d8 would be entered as [Ar]4s^23d^8.)
The Correct Answer and Explanation is:
Correct Answer:
[Ne]3s²3p²
Explanation
The ground-state electron configuration of an element describes the arrangement of its electrons in orbitals when the atom is in its lowest energy state. To write the electron configuration using noble-gas shorthand, we substitute the configuration of the nearest preceding noble gas with its symbol in brackets.
Step 1: Determine the atomic number of silicon.
Silicon (Si) has an atomic number of 14, meaning it has 14 electrons in its neutral ground state.
Step 2: Identify the nearest noble gas with a lower atomic number.
The noble gases are:
- He (Z=2)
- Ne (Z=10)
- Ar (Z=18)
- etc.
The nearest noble gas before Si is Neon (Ne, Z = 10). Neon has the configuration 1s² 2s² 2p⁶, accounting for 10 electrons.
Step 3: Add the remaining electrons after [Ne].
Si has 14 electrons in total, so we subtract 10 (from Ne), leaving 4 electrons to distribute.
These 4 electrons go into the third energy level:
- 2 electrons fill the 3s orbital → 3s²
- 2 electrons go into the 3p orbital → 3p²
Thus, the configuration is:
[Ne]3s²3p²
This configuration shows that the valence electrons for silicon are in the third shell, specifically in the 3s and 3p orbitals. These 4 valence electrons (2 from 3s and 2 from 3p) explain silicon’s typical tetravalent bonding behavior, such as in silicon dioxide (SiO₂) or silicon-based semiconductors.
Using the noble-gas shorthand simplifies electron configurations, especially for elements with many electrons, by eliminating the need to write the entire configuration of core electrons. This is especially useful in chemistry when analyzing or comparing valence electron arrangements, which are most relevant to chemical reactivity and bonding.Correct Answer:
[Ne]3s²3p²
The nearest noble gas before Si is Neon (Ne, Z = 10). Neon has the configuration 1s² 2s² 2p⁶, accounting for 10 electrons.
Step 3: Add the remaining electrons after [Ne].
Si has 14 electrons in total, so we subtract 10 (from Ne), leaving 4 electrons to distribute.
These 4 electrons go into the third energy level:
- 2 electrons fill the 3s orbital → 3s²
- 2 electrons go into the 3p orbital → 3p²
.