Calculate the number of valence electrons in Astatine using its electron configuration step by step.
Determine the number of valence electrons in Astatine (At, Element 85)
The abbreviated (condensed) ground electronic configuration for Astatine is:
[Xe] 4f14 5d10 6s2 6p5
Electrons in atomic orbitals outside the [Xe] core are the outermost electrons:
4f14 5d10 6s2 6p5
Extract the principle quantum number, n, and number of electrons from the electron configuration:
|Electron Configuration||n||Orbital||Number of Electrons|
The outermost electrons with the largest principal quantum number (in this case, n = 6) are valence electrons.
Astatine (At) has 7 (2 + 5) valence electrons.