To determine the electron configuration for dysprosium (Dy) and americium (Am) in noble-gas notation, we can follow these steps:
### Dysprosium (Dy)
1. Determine Position in the Periodic Table:
- Dysprosium (Dy) has an atomic number of 66.
2. Identify the Previous Noble Gas:
- The noble gas preceding Dy is Xenon (Xe), with an atomic number of 54.
3. Build the Electron Configuration:
- After Xenon, we fill the orbitals in the following order: 6s, 4f, and then 5d if needed.
- The total electrons to account for are [tex]\( 66 - 54 = 12 \)[/tex] electrons.
- The electron configuration is:
- [tex]\( [Xe] = \)[/tex] accounts for 54 electrons
- [tex]\( 6s^2 = 2 \)[/tex] electrons (now 56 electrons)
- [tex]\( 4f^{10} = 10 \)[/tex] electrons (bringing the total to 66 electrons)
4. Write in Noble-Gas Notation:
- Combining these, we get [tex]\( [Xe] 4f^{10} 6s^2 \)[/tex].
### Americium (Am)
1. Determine Position in the Periodic Table:
- Americium (Am) has an atomic number of 95.
2. Identify the Previous Noble Gas:
- The noble gas preceding Am is Radon (Rn), with an atomic number of 86.
3. Build the Electron Configuration:
- After Radon, we fill the orbitals in the following order: 7s, 5f, and then 6d if needed.
- The total electrons to account for are [tex]\( 95 - 86 = 9 \)[/tex] electrons.
- The electron configuration is:
- [tex]\( [Rn] = \)[/tex] accounts for 86 electrons
- [tex]\( 7s^2 = 2 \)[/tex] electrons (now 88 electrons)
- [tex]\( 5f^7 = 7 \)[/tex] electrons (bringing the total to 95 electrons)
4. Write in Noble-Gas Notation:
- Combining these, we get [tex]\( [Rn] 5f^7 7s^2 \)[/tex].
Thus,
- The noble-gas notation electron configuration for dysprosium (Dy) is [tex]\( [Xe] 4f^{10} 6s^2 \)[/tex].
- The noble-gas notation electron configuration for americium (Am) is [tex]\( [Rn] 5f^7 7s^2 \)[/tex].
