1. Monday Oct 20 Objective: Write the electronic configuration of any element. Checkpoint: How many different photons of light can an atom give off if it has 4 energy levels? HW: Emission spectrum lab (due Tuesday)

3. Electromagnetic Spectrum

4. Emission Spectroscopy Lab Pre-lab questions: 1.According to the modern theory of the atom, where may an atom’s electrons be found? 2.How do electrons become “excited”? 3.What form of energy emission accompanies the return of excited electrons to the ground state? 4.Assume that an atom has a total of four possible energy levels and that an electron can jump up or down between any of these energy levels. Draw a model of these energy levels, and use it to predict the maximum number of spectral lines in the emission spectrum.

5. Emission Spectroscopy Lab Data : Sunlight/white light Fluorescent light

6. Emission Spectroscopy Lab Post-lab questions: 1.Compare the spectra produced by sunlight (white light) and fluorescent sources. What are the similarities? What are the differences? 2.Some elements have the same color, but brighter spectral lines than others. How can the difference in the brightness be explained? 3.Prior to its discovery on Earth, the existence of helium was first confirmed in the sun. Explain how this can be possible.

8. 8 Erwin Schrödinger Quantum Mechanical Model – Modern model – Estimates the probability of finding an electron within a certain volume of space surrounding the nucleus – Where you find the electron 90% of the time

9. 9 Energy Levels Principal quantum numbers (n) identify the energy levels in an atom – Tells you how far away the electron is from the nucleus – There are 1-7 energy levels, correlates with period numbers – Maximum number of 2n 2 electrons per level

10. 10 Atomic Orbitals Atomic orbitals are more specific regions within each energy level where electrons are found – Highest probability of finding an electron – designated by letters s,p,d,f – Each orbital can hold 2 electrons

11. 11 s, p, d, f orbitals

13. 13 Electron Cloud Picture

14. Every atom has energy levels in which electrons can be found. Formula: 2n 2 (where n = energy level) Energy LevelTotal # electrons 12 28 318 432

15. Each orbital can hold 2 electrons Orbital Type# of Orbitals# of total electrons s-orbital12 p-orbital3 6 d-orbital5 10 f-orbital7 14

16. Writing Electron Configurations Purpose: to summarize where the electrons are (which energy level and orbital) – Electron configuration notation (long form) – Noble gas notation (short form) – Orbital notation (picture form)

18. Write e-configs for: Carbon Magnesium Arsenic Gold