Electrons in Atoms Electron Configuration Orbital Notation Essential question: What correlation is there between electron configuration and orbital notation?

Electron Configuration Essential question: What correlation is there between electron configuration and orbital notation? Electron Configuration A form of notation which shows how the electrons are distributed among the various atomic orbital and energy levels Example of e- configuration for Hydrogen: 1s1 Total # of electrons in that sublevel. 1st column of s-block S-Block Principle Quantum number which stands for the energy level

Periodic Patterns Yellow represents the s-block Pink represents the p-block Green represents the d-block Orange represents the f-block S-block S-block d-block p-block f-block

Learning Check What element would have an electron configuration ending in 4s1? Potassium

Order of filling sublevels 1s2 2s2 2p6 3s2 3p6 4s2 You must fill in each sublevel with its maximum number of electrons before you move to the next energy level (Aufbau Principle) Sublevel (block) # of orbitals Maximum # of e- S 1 2 p 3 6 d 5 10 f 7 14

Examples e- configuration for Oxygen Oxygen has 8 electrons and is in period 2 1s2 2s2 2p4

Practice Write the e- configuration for the following elements: Helium Sulfur Calcium Valence electrons are the electrons on the outermost (highest) energy level. Place a box around the valence electrons in the examples above.

Nobel Gas Electron Configuration Shows the energy levels and sublevels of the valence electrons and any d or f electrons. In Nobel Gas Configurations – the last Nobel gas on the periodic table BEFORE the element of interest is placed in brackets to represent the core electrons. The Nobel gas is then followed by the valence electrons and any electrons from the d or f subshells.

Examples Noble Gas Electron Configuration for Oxygen [He]2s22p4 Nobel Gas Electron Configuration for Iron [Ar]4s23d6 *NOTE- If asked to give the electron configuration of a Nobel gas you cannot use Nobel gas configuration – you must use standard electron configuration.

Practice Write the Noble gas electron configuration for the following elements: Sulfur Calcium Bromine

Orbital Notation Every box represents an orbital Sublevel (block) # of orbitals Maximum # of e- S 1 2 p 3 6 d 5 10 f 7 14 Every box represents an orbital Every arrow represents electrons

General Rules Pauli Exclusion principle Hund’s rule Every orbital can only hold 2 electrons with opposite spins Hund’s rule Within a sublevel, place one e- per orbital before pairing them. Right WRONG

Example: Orbital Notation for Oxygen: Remember: 1s2 2s2 2p4 Orbital Notation for Oxygen: You know the e- configuration for oxygen is 1s22s22p4 Remember: Every orbital is represented by a box Every orbital holds a maximum of 2 electrons s-block represented by 1 orbital p-block represented by 3 orbitals

Practice Show orbital notation for the following elements: Helium Sulfur Calcium