Electron configuration

• the s subshell contains 1 orbital and a maximum of 2 electrons
• the p sub shell contains 3 orbitals and a maximum of 6 electrons
• the d subshell contains 5 orbitals and a maximum of 10 electrons
• the f sub shell contains 7 orbitals and a maximum of 14 electrons
• each shell is given a principle quantum number. the further the shell from the nucleus the higher the number
• the 4s subshell has a lower energy level than the 3p subshell even though it has a higher principle quantum number. this means the 4s subshell fills up first
• Nobel gas symbols in square brackets can be used to shorten electron configurations.
• chromium and copper are exceptions to the general rules of electron configurations
• chromium and copper donate one of their 4s electrons to the 3d subshell as they’d rather have a more stable full/half-full 3d subshell