Answer :
Sure, let's break down the noble-gas notation electron configurations for calcium (Ca) and promethium (Pm) step-by-step.
### Calcium (Ca)
1. Determine the Atomic Number: Calcium has an atomic number of 20, meaning it has 20 electrons.
2. Find the Nearest Noble Gas Preceding Calcium: The nearest noble gas before calcium is argon (Ar), which has an atomic number of 18. This means argon has the electron configuration of [tex]\(1s^2 2s^2 2p^6 3s^2 3p^6\)[/tex].
3. Write the Configuration Beyond the Noble Gas: After argon, we need to account for 2 more electrons to reach calcium. These electrons will go into the 4s orbital.
So, the noble-gas notation for calcium is:
[tex]\[ \text{Ca:} \, [\text{Ar}] 4s^2 \][/tex]
### Promethium (Pm)
1. Determine the Atomic Number: Promethium has an atomic number of 61, meaning it has 61 electrons.
2. Find the Nearest Noble Gas Preceding Promethium: The nearest noble gas before promethium is xenon (Xe), which has an atomic number of 54. Xenon has the electron configuration of [tex]\(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6\)[/tex].
3. Write the Configuration Beyond the Noble Gas: After xenon, we need to account for the remaining 7 electrons. These electrons will fill the 4f and 6s orbitals.
- 5 electrons will go into the 4f orbital.
- 2 electrons will go into the 6s orbital.
So, the noble-gas notation for promethium is:
[tex]\[ \text{Pm:} \, [\text{Xe}] 4f^5 6s^2 \][/tex]
### Final Answer
- Calcium (Ca): [tex]\([Ar] 4s^2\)[/tex]
- Promethium (Pm): [tex]\([Xe] 4f^5 6s^2\)[/tex]
I hope this detailed explanation helps you understand how to write the noble-gas electron configurations for calcium and promethium!
### Calcium (Ca)
1. Determine the Atomic Number: Calcium has an atomic number of 20, meaning it has 20 electrons.
2. Find the Nearest Noble Gas Preceding Calcium: The nearest noble gas before calcium is argon (Ar), which has an atomic number of 18. This means argon has the electron configuration of [tex]\(1s^2 2s^2 2p^6 3s^2 3p^6\)[/tex].
3. Write the Configuration Beyond the Noble Gas: After argon, we need to account for 2 more electrons to reach calcium. These electrons will go into the 4s orbital.
So, the noble-gas notation for calcium is:
[tex]\[ \text{Ca:} \, [\text{Ar}] 4s^2 \][/tex]
### Promethium (Pm)
1. Determine the Atomic Number: Promethium has an atomic number of 61, meaning it has 61 electrons.
2. Find the Nearest Noble Gas Preceding Promethium: The nearest noble gas before promethium is xenon (Xe), which has an atomic number of 54. Xenon has the electron configuration of [tex]\(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6\)[/tex].
3. Write the Configuration Beyond the Noble Gas: After xenon, we need to account for the remaining 7 electrons. These electrons will fill the 4f and 6s orbitals.
- 5 electrons will go into the 4f orbital.
- 2 electrons will go into the 6s orbital.
So, the noble-gas notation for promethium is:
[tex]\[ \text{Pm:} \, [\text{Xe}] 4f^5 6s^2 \][/tex]
### Final Answer
- Calcium (Ca): [tex]\([Ar] 4s^2\)[/tex]
- Promethium (Pm): [tex]\([Xe] 4f^5 6s^2\)[/tex]
I hope this detailed explanation helps you understand how to write the noble-gas electron configurations for calcium and promethium!
