Alright! Let's determine the electron configuration of aluminum (Al) and arsenic (As) in noble-gas notation step by step.
### Aluminum (Al)
1. Determine the atomic number of aluminum: The atomic number of aluminum is 13. This means aluminum has 13 electrons.
2. Identify the noble gas preceding aluminum: The noble gas preceding aluminum on the periodic table is neon (Ne), which has an atomic number of 10.
3. Determine the remaining electrons and their configuration: After accounting for the 10 electrons in neon, we have [tex]\( 13 - 10 = 3 \)[/tex] electrons left to place in orbitals.
4. Configuration beyond neon:
- The next available sublevel is the [tex]\( 3s \)[/tex] orbital, which can hold up to 2 electrons.
- The remaining 1 electron will go into the [tex]\( 3p \)[/tex] orbital.
Therefore, the electron configuration of aluminum (Al) in noble-gas notation is:
[tex]\[ [ \operatorname{Ne} ] 3s^2 3p^1 \][/tex]
### Arsenic (As)
1. Determine the atomic number of arsenic: The atomic number of arsenic is 33. This means arsenic has 33 electrons.
2. Identify the noble gas preceding arsenic: The noble gas preceding arsenic on the periodic table is argon (Ar), which has an atomic number of 18.
3. Determine the remaining electrons and their configuration: After accounting for the 18 electrons in argon, we have [tex]\( 33 - 18 = 15 \)[/tex] electrons left to place in orbitals.
4. Configuration beyond argon:
- The next available sublevels, in the order they fill, are:
- [tex]\( 4s^2 \)[/tex] (2 electrons in [tex]\( 4s \)[/tex] orbital)
- [tex]\( 3d^{10} \)[/tex] (10 electrons in [tex]\( 3d \)[/tex] orbital)
- [tex]\( 4p^3 \)[/tex] (3 electrons in [tex]\( 4p \)[/tex] orbital)
Therefore, the electron configuration of arsenic (As) in noble-gas notation is:
[tex]\[ [ \operatorname{Ar} ] 4s^2 3d^{10} 4p^3 \][/tex]
### Summary
The noble-gas notation electron configurations are:
- Aluminum (Al): [tex]\([ \operatorname{Ne} ] 3s^2 3p^1\)[/tex]
- Arsenic (As): [tex]\([ \operatorname{Ar} ] 4s^2 3d^{10} 4p^3\)[/tex]
