1. Bohr Rutherford and Beyond

3. Inside the Atom - Protons Positive charge Mass of ~1 atomic mass unit (amu). Found in nucleus Determines type of atom (determines element) Indicates number of protons in one atom of that element.

4. Inside the Atom- Electrons Negative charge Mass of 1/2000 of a proton (negligible) Orbit the nucleus of the atom

5. Inside the Atom- Neutrons Neutral particles. Neither positive or negative charge Mass of ~1 amu Found in the nucleus of the atom Number of neutrons in an atom can vary  isotopes

6. Model of The Atom Cannot be broken down further Nucleus contains protons and neutrons, shells contain electrons Neutrons and protons have vast majority of atoms mass. Electrons have negligible mass.

7. Bohr-Rutherford Model Electrons move around the nucleus in a circular orbits Electrons arranged around the nucleus and only on certain orbits (orbitals). Atom’s try to have 8 electrons on outermost orbital 2 on first level 8 on every other level Further from nucleus  More potential energy Electrons need energy to move to higher level Electrons give off energy if moved to lower level

8. Phosphorous atom (#15) Bohr-Rutherford Diagrams 15p 16n Summarizes protons, neutrons and electrons Neutrons = weight - protons

9. 3. Draw the second orbit with the remaining electrons, 5. Nitrogen atom 2. Draw the first orbit with the maximum electrons allowed, 2. Sample Bohr- Rutherford Diagrams Create a diagram for Nitrogen. 1.Determine the number of electrons, 7 (same as atomic number). 7p 7n 4. Draw the nucleus with the protons and neutrons.

10. An extra degree of difficulty... Bohr Model has limitations Bohr diagrams limited to the octet rule Cannot diagram transition metals, actinides, lanthanides Orbitals as known as shells, and shells may consist of numerous subshells.

11. Subshell Blocks

12. Quantum Mechanical Model Evolution of Bohr Model Does not define exact path of electron Energy levels divided into sublevels (s, p, d and f) of orbitals Only 4 energy levels Level 2  s & p orbital Level 3  s, p or d orbital Level 4  s, p, d or f orbital

13. Order of Orbitals 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 8s, 5g, 6f, 7d, 8p, and 9s

14. Electron Configurations 1) The Aufbau Principle Electrons enter orbitals of lowest energy first. 2) The Pault Exclusion Principle An atomic orbital may contain at most 2 electrons. 3) Hund’s Rule When electrons occupy orbitals, one electron enters each orbital of an energy level before any pairing occurs.

15. So what does this look like?

16. Examples