Essential Questions and Objectives • How does the configuration of electrons affect the atom’s properties? You’ll be able to: – Draw an orbital diagram for an element – Determine the electron configuration for an element – Explain the Pauli exclusion principle, Aufbau principle and Hund’s Rule Warm up Set your goals and curiosities for the unit on your tracker. Have your comparison table out for a stamp Bohr v QMM What are some features of the quantum mechanical model of the atom that are not included in the Bohr model? Quantum Mechanical Model • Electrons do not travel around the nucleus of an atom in orbits • They are found in energy levels at different distances away from the nucleus in orbitals • Orbital – region in space where there is a high probability of finding an electron. Atomic Orbitals Electrons cannot exist between energy levels (just like the rungs of a ladder). Principal quantum number (n) indicates the relative size and energy of atomic orbitals. n specifies the atom’s major energy levels also called the principal energy levels. Energy sublevels are contained within the principal energy levels. Ground-State Electron Configuration The arrangement of electrons in the atom is called the electron configuration. Shows where the electrons are - which principal energy levels, which sublevels - and how many electrons in each available space Orbital Filling • The order that electrons fill up orbitals does not follow the order of all n=1’s, then all n=2’s, then all n=3’s, etc. Electron configuration for... Oxygen How many electrons? There are rules to follow to know where they go ... • Your group’s task: GOAL: Explain the electron configuration rule 1. Record the definitions of your rule or principle in your notes. 2. Match the rule or principle with your example and nonexample card. 3. Explain the rule to the class. How is it broken and followed? You will present your group’s findings to the class. Use the Periodic Table! • An easy way to remember this is to use the periodic table--it is arranged to show how these orbitals are filled. Order of Orbitals—Periodic Table Practice Work on the Electron Configuration Practice 1 Check in for answers. Complete for HW • Hund’s rule states that single electrons with the same spin must occupy each degenerate orbital before additional electrons with opposite spins can occupy the same energy level orbitals. • Hund’s rule states that single electrons with the same spin must occupy each degenerate orbital before additional electrons with opposite spins can occupy the same energy level orbitals. • Hund’s rule states that single electrons with the same spin must occupy each degenerate orbital before additional electrons with opposite spins can occupy the same energy level orbitals. • Hund’s rule states that single electrons with the same spin must occupy each degenerate orbital before additional electrons with opposite spins can occupy the same energy level orbitals. • Hund’s rule states that single electrons with the same spin must occupy each degenerate orbital before additional electrons with opposite spins can occupy the same energy level orbitals. • Hund’s rule states that single electrons with the same spin must occupy each degenerate orbital before additional electrons with opposite spins can occupy the same energy level orbitals. The Pauli exclusion principle states that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins. The Pauli exclusion principle states that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins. The Pauli exclusion principle states that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins. The Pauli exclusion principle states that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins. The Pauli exclusion principle states that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins. The Pauli exclusion principle states that a maximum of two electrons can occupy a single orbital, but only if the electrons have opposite spins. • The aufbau principle states that each electron occupies the lowest energy orbital available. • The aufbau principle states that each electron occupies the lowest energy orbital available. • The aufbau principle states that each electron occupies the lowest energy orbital available. • The aufbau principle states that each electron occupies the lowest energy orbital available. • The aufbau principle states that each electron occupies the lowest energy orbital available. • The aufbau principle states that each electron occupies the lowest energy orbital available. .