Condensed Electron Configuration

• What is the condensed electron configuration of bromine?

Valence Electrons

• What are bromine’s valence electrons?
• How many valence electrons does titanium have?
• When does the d-block count toward an atom’s number of valence electrons?

Energy Diagrams

• Aufbau Principle: electrons fill the lowest energy orbitals first.
• Hund’s Rule: Don’t pair up electrons until you have to.
• Pauli Exclusion Principle: no two electrons in the same atom can have the same four quantum numbers. In other words, no two electrons in the same atom can have the exact same address.