Answer :
Let's determine the electron configuration for bromine (Br), which has an atomic number of 35. The atomic number indicates the number of electrons in a neutral atom.
We will fill the electron orbitals according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle.
1. Understand the order of orbital filling: Electrons are distributed among the orbitals in order of increasing energy levels. The order is as follows:
- 1s
- 2s
- 2p
- 3s
- 3p
- 4s
- 3d
- 4p
- and so on.
2. Assign electrons to orbitals:
- 1s: 2 electrons
- 2s: 2 electrons
- 2p: 6 electrons
- 3s: 2 electrons
- 3p: 6 electrons
- 4s: 2 electrons
- 3d: 10 electrons
- 4p: 5 electrons
Now let's add the electrons step-by-step:
- 1s²: 2 electrons (total 2)
- 2s²: 2 electrons (total 4)
- 2p⁶: 6 electrons (total 10)
- 3s²: 2 electrons (total 12)
- 3p⁶: 6 electrons (total 18)
- 4s²: 2 electrons (total 20)
- 3d¹⁰: 10 electrons (total 30)
- 4p⁵: 5 electrons (total 35)
Putting all these together, the electron configuration for bromine is:
[tex]\[ \text{Br}: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^5 \][/tex]
Comparing this with the given options:
1. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^{10} 4 p^5 \)[/tex]
2. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^{10} 4 p^6 \)[/tex]
3. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^4 4 s^2 3 d^{10} 4 p^5 \)[/tex]
4. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^9 4 p^5 \)[/tex]
The correct electron configuration for bromine corresponds to the first option:
[tex]\[ 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^5 \][/tex]
So the correct answer is option 1.
We will fill the electron orbitals according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle.
1. Understand the order of orbital filling: Electrons are distributed among the orbitals in order of increasing energy levels. The order is as follows:
- 1s
- 2s
- 2p
- 3s
- 3p
- 4s
- 3d
- 4p
- and so on.
2. Assign electrons to orbitals:
- 1s: 2 electrons
- 2s: 2 electrons
- 2p: 6 electrons
- 3s: 2 electrons
- 3p: 6 electrons
- 4s: 2 electrons
- 3d: 10 electrons
- 4p: 5 electrons
Now let's add the electrons step-by-step:
- 1s²: 2 electrons (total 2)
- 2s²: 2 electrons (total 4)
- 2p⁶: 6 electrons (total 10)
- 3s²: 2 electrons (total 12)
- 3p⁶: 6 electrons (total 18)
- 4s²: 2 electrons (total 20)
- 3d¹⁰: 10 electrons (total 30)
- 4p⁵: 5 electrons (total 35)
Putting all these together, the electron configuration for bromine is:
[tex]\[ \text{Br}: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^5 \][/tex]
Comparing this with the given options:
1. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^{10} 4 p^5 \)[/tex]
2. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^{10} 4 p^6 \)[/tex]
3. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^4 4 s^2 3 d^{10} 4 p^5 \)[/tex]
4. [tex]\( 1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^9 4 p^5 \)[/tex]
The correct electron configuration for bromine corresponds to the first option:
[tex]\[ 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^5 \][/tex]
So the correct answer is option 1.