Electron configuration

Electron configuration

1. Emission spectra

   • Produced when photons are emitted from atoms as excited electrons return to a lower energy level
   • Electromagnetic radiation comes in different forms. All forms travel at the same speed of light but have different wavelengths. The higher energy forms have shorter wavelengths and higher frequencies

2. Electromagnetic spectrum

   • Lowest energy: Radio waves. Highest energy: Gamma rays.
   • Colors (from lowest to highest energy): Red, Orange, Yellow, Green, Blue, Indigo, Violet

3. Continuous- and Line spectrum

   • Continuous Spectrum
     • Produced when WHITE light is passed through a prism. Shows ALL colors in an unbroken sequence of frequencies.
   • Line spectrum
     • AKA. Emission spectrum has sharp lines produced by SPECIFIC frequencies of light. Produced by atoms and ions as they fall back to lower energy levels. We can identify unknown elements as different element shave different line spectra.
     • Line emission spectrum of hydrogen provides evidence for the existence of electrons in discrete energy levels, which converge at higher energies.

4. Hydrogen

   • Gives out energy when an electron falls from a higher to a lower energy level. Hydrogen also produces visible light when an electron fall to the SECOND energy level (n=2). Transition to n=1 is a higher energy change and this is in the ultraviolet region of the spectrum. When an electron falls to the 3rd or higher energy levels, Infrared radiation is produced.

5. Orbitals

   • Hold a maximum of electrons : 2n^2
     • Division of main energy levels into S, P, D and F sub-levels of successively higher energies
       • Lowest energy: S Highest energy: F
   • "S" has only one shape: Spherical
     • "P" are dumbbell-shaped Higher in energy than the "s". TOTAL OF 6 electrons
       • "D" orbitals are clover-leaf shaped and have a total of 10 electrons. Higher in energy than "P"
         • "F" orbitals have irregular shapes due to Quantum tunnelling. Total of 14 electrons and have the highest energy level out of all orbitals.

6. Means the number of electrons in each sub-level

7. Exceptions to E. configurations

   • Chromium ends in 3d^5, 4s^1 Copper ends in: 3d^10, 4s^1

8. Valence electrons = Outer shell electrons