Valence Electrons in Bromine (Br)
Calculate the number of valence electrons in Bromine using its electron configuration step by step.
Valence Electrons in Bromine
Determine the number of valence electrons in Bromine (Br, Element 35)
Step 1: Look up the electronic configuration for Bromine
The abbreviated (condensed) ground electronic configuration for Bromine is:
[Ar] 3d10 4s2 4p5
Calculate Electronic Configuration for Bromine
Step 2: Identify the outermost electrons using the electronic configuration
Electrons in atomic orbitals outside the [Ar] core are the outermost electrons:
3d10 4s2 4p5
Step 3: Use the principle quantum number to identify the valence electrons
Extract the principle quantum number, n, and number of electrons from the electron configuration:
| Electron Configuration | n | Orbital | Number of Electrons |
|---|---|---|---|
| 3d10 | 3 | d | 10 |
| 4s2 | 4 | s | 2 |
| 4p5 | 4 | p | 5 |
The outermost electrons with the largest principal quantum number (in this case, n = 4) are valence electrons.
Answer
Bromine (Br) has 7 (2 + 5) valence electrons.
