1. Electron configuration-2.2

2. continuous spectrum vs. line spectrum
violet- 410 nm
blue- 434 nm
blue-green- 486 nm
red- 656 nm

3. Emission spectrum of hydrogen
consists of a series of lines of different colors
N=1, 2, 3, 4, 5, 6
Violet transitions from n=6 to n=2
Blue transitions from n=5 to n=2
Blue-green transitions from n=4 to n=2
Red transitions from n=3 to n=2
light can’t be seen under 400 nm (n=1)

4. Energy States Ground-state and excited-state
Photon- discrete amount of energy -When electron falls down from excited state light is emitted
different color lights, dependent on wavelength (energy released)

5. Sublevels (orbitals) s, p, d, f
Maximum number of electrons in sublevels (orbital)
s- 2 (99% chance of finding electron)
p- 6 (Px, Py, Pz three atomic orbitals)
d- 10 (five orbitals)
f- 14 (seven orbitals)

6. Orbitals
every orbital can only contain/hold a maximum of 2 electrons, with opposite spins example:
electrons fill at the lowest-energy orbital first before the next (s, p, d, and then f)

7. isoelectronic series

8. Electron Configuration-looks like
fill in the s orbital first, then p, then d, and finally f if needed.
example:
k (potassium) z=19 1s2 2s2 2p6 3s2 3p6 4s1 (keep in mind that 4s fills before 3d)
Z represents the atomic number (number of protons)
anion add electrons, cation remove electrons

9. Blocks on the periodic table
main group elements:
1-2 & first element on 18 (helium): s block
3-12: d block
13-18: p block
f block at the bottom
*knowing the blocks will save you time when writing out the electron configuration*

10. Condensed electron configuration
[ nearest noble gas] + valence electrons
example: Br 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p5
alternative [Ar] 3d10 4s2 4p5
useful when there is an element w/ a lot of electrons

11. practice problems
Write the full electron configuration of Si (silicon), z=14
Draw an orbital diagram of N (nitrogen), z=7
Write the condensed electron configuration of Zn (zinc), z=30
Write the condensed electron configuration of As2- (arsenic), z=33
In the emission spectrum of hydrogen, which electronic transition would produce a line in the visible region of the electromagnetic spectrum? (from IB textbook) A. n=2 n=1 B. n=3 n=2 C. n=2 n=3 D. n=∞ n=1

12. Answers
1s2 2s2 2p6 3s2 3p B, because energy level is decreasing, light is emitted 2.
3. [Ar] 4s2 3d10
4. [Ar] 4s2 3d10 4p1 2p 2s 1s