What is the order of energy levels and sub-shells in increasing energy?
1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p
How many orbitals are in an s subshell?
1 orbital (can hold 2 electrons)
How many orbitals are in a p subshell?
3 orbitals (can hold 6 electrons total)
How many orbitals are in a d subshell?
5 orbitals (can hold 10 electrons total)
How many orbitals are in an f subshell?
7 orbitals (can hold 14 electrons total)
What is the maximum number of electrons that can fit in the n=3 shell?
18 electrons (3s² 3p⁶ 3d¹⁰)
Which subshell fills first, 4s or 3d?
4s fills before 3d (but 4s electrons are lost first in ions)
Why does chromium have an unusual electron configuration?
It adopts [Ar] 4s¹ 3d⁵ for extra stability from half-filled d subshell
Why does copper have an unusual electron configuration?
It adopts [Ar] 4s¹ 3d¹⁰ for full d-subshell stability
What is Hund’s rule?
Electrons fill degenerate orbitals singly with parallel spins before pairing
what is removed first between 4s and 3d electrons
4s electrons are removed before 3d electrons
what is an orbital
an orbital is a region of space around the nucleus where an electron is most likely to be found. Each orbital can hold a maximum of two electrons with opposite spins
what is a subshell
a group of orbitals with the same energy level within an electron shell
how do you do electron configurations with ions
If it is a positive charge take one electron away from the energy level. If it is negative add electrons.
