What is the electron configuration for the cobalt (Co) atom in its ground state? a. 1s22s22p63s23p63d7 b. [Ar]3d7 c. 1s22s22p63s23p63d74s2 d. [Kr]4s23d7 2. Corrected_text: What is the electron configuration for the calcium (Ca) atom in its ground state? a. 1s22s22p63s23p63d64s2 b. [Ar]4s2 c. 1s22s22p63s23p63d2 d. [Kr]4s2 3. Corrected_text: Which ion has the ground-state electron configuration: 1s22s22p63s23p4? Check all possible. a. P- b. Cl- c. S2- d. Ar2+ 4. Corrected_text: The ground-state electron configuration of the Sb3- ion is: a. [Kr]4d105s25p6 b. [Kr]5s25p6 c. [Kr]4d105s25p6 d. [Kr]4d105s2
The Correct Answer and Explanation is:
. Electron configuration of Cobalt (Co) atom in its ground state
The atomic number of cobalt (Co) is 27, meaning it has 27 electrons in its neutral state. The electron configuration can be written by filling the orbitals in the order of increasing energy, following the Aufbau principle, Hund’s rule, and Pauli exclusion principle. Here’s the step-by-step breakdown:
- First, the 1s orbital is filled with 2 electrons: 1s².
- Then, the 2s orbital is filled with 2 electrons: 2s².
- The 2p orbital can hold 6 electrons: 2p⁶.
- The 3s orbital is filled with 2 electrons: 3s².
- The 3p orbital is filled with 6 electrons: 3p⁶.
- Now, we move to the 3d orbital, which holds 7 electrons for Co: 3d⁷.
Thus, the electron configuration for the ground state of cobalt is:
1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s².
So, the correct answer is c. 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s².
2. Electron configuration of Calcium (Ca) atom in its ground state
The atomic number of calcium (Ca) is 20, meaning it has 20 electrons. The electron configuration follows the same process as for cobalt:
- First, the 1s orbital is filled with 2 electrons: 1s².
- The 2s orbital is filled with 2 electrons: 2s².
- The 2p orbital holds 6 electrons: 2p⁶.
- The 3s orbital holds 2 electrons: 3s².
- Finally, the 4s orbital holds the remaining 2 electrons: 4s².
Thus, the electron configuration for the ground state of calcium is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
So, the correct answer is b. [Ar] 4s². This is the shorthand notation, where [Ar] represents the electron configuration of Argon (18 electrons) and 4s² is added.
3. Ion with the electron configuration 1s² 2s² 2p⁶ 3s² 3p⁴
This configuration corresponds to an element that has 18 electrons in total (since 2 + 2 + 6 + 2 + 4 = 18). This configuration is typical for the S²⁻ ion, as sulfur (S) has 16 electrons in its neutral state, and by gaining 2 electrons (to become S²⁻), it reaches the electron configuration of Argon.
- P⁻: Phosphorus has 15 electrons, so it would need to gain 3 electrons to have 18, so this does not match.
- Cl⁻: Chlorine has 17 electrons, and by gaining 1 electron, it would also reach 18 electrons, so this is a possible match.
- S²⁻: Sulfur, as explained, gains 2 electrons to achieve this configuration, so this is also a correct match.
- Ar²⁺: Argon has 18 electrons, and the Ar²⁺ ion would have lost 2 electrons, making this configuration incorrect.
Thus, the ions with the ground-state electron configuration 1s² 2s² 2p⁶ 3s² 3p⁴ are Cl⁻ and S²⁻. So, the correct answers are b. Cl⁻ and c. S²⁻.
4. Electron configuration of Sb³⁻ ion
The atomic number of antimony (Sb) is 51, and in its neutral state, it has 51 electrons. The electron configuration of Sb in its neutral state is:
[Kr] 5s² 4d¹⁰ 5p³.
When antimony gains 3 electrons to become the Sb³⁻ ion, the electron configuration changes to:
[Kr] 5s² 4d¹⁰ 5p⁶.
So, the correct answer is a. [Kr] 4d¹⁰ 5s² 5p⁶.
