REVIEW DAY

Orbitals are described with 2 different numbers called Quantum Numbers 1)Principal Quantum Number (n) Integer values that describe the energy of the orbital Larger n means larger average distance of an electron from nucleus (thus larger orbital) 2)Angular Momentum Quantum Number (l) Tells us the “shape” of the orbitals

Orbital Diagrams

Electron Configuration 1s11s1 row # shell # possibilities are rows subshell possibilities are s, p, d, or f 4 subshells group # # valence e- possibilities are: s: 1 or 2 p: 1-6 d: 1-10 f: 1-14 Total e- should equal Atomic # What element has an electron configuration of 1s 1 ?

The 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)

Orbital filling table

RULES!! Memorize These!! ■Three rules (To MEMORIZE) –Aufbau: Electrons fill orbitals starting in the lowest energy levels and moving out. –Pauli: No two electrons can have the same spin and occupy the same orbital. –Hunds: Electrons fill each orbital singly before any orbital get a second electron.

Shorthand Notation ■Step 1: Find the closest noble gas to the atom (or ion), WITHOUT GOING OVER the number of electrons in the atom (or ion). Write the noble gas in brackets [ ]. ■Step 2: Find where to resume by finding the next energy level. ■Step 3: Resume the configuration until it’s finished.

Shorthand Notation ■Chlorine –Longhand is 1s 2 2s 2 2p 6 3s 2 3p 5 You can abbreviate the first 10 electrons with a noble gas, Neon. [Ne] replaces 1s 2 2s 2 2p 6 The next energy level after Neon is 3 So you start at level 3 on the diagonal rule (all levels start with s) and finish the configuration by adding 7 more electrons to bring the total to 17 [Ne] 3s 2 3p 5

Speed = wavelength x frequency c = (length/second) = (length/cycle) x (cycle/second) Hence, = c / and = c /

Hydrogen spectrum ■Emission spectrum because these are the colors it gives off or emits ■Called a line spectrum. ■There are just a few discrete lines showing 410 nm 434 nm 486 nm 656 nm Spectrum

Energy Example Problems ■Calculate the frequency of radiation with a wavelength of 442 nm. ■Calculate the frequency of radiation with a wavelength of 4.92 cm. 1) Convert nm to m: 442 nm x (1 m / 10 9 nm) = 4.42 x 10¯ 7 m 2) Substitute into λν = c: (4.42 x 10¯ 7 m) (x) = 3.00 x 10 8 m s¯ 1 x = 6.79 x s¯ 1 Since the wavelengths are already in cm, we can use c = 3.00 x cm s¯ 1 and not have to do any conversions at all. (4.92 cm) (x) = 3.00 x cm s¯ 1 x = 6.10 x 10 9 s¯ 1

Example What is the frequency of radiation with a wavelength of 5.00 x 10¯ 8 m? In what region of the electromagnetic spectrum is this radiation? Solution: 1) Use λν = c to determine the frequency: (5.00 x 10¯ 8 m) (x) = 3.00 x 10 8 m/s x = 6.00 x s¯ 1 2) Determine the electromagnetic spectrum region: Consult a convenient reference source. This frequency is right in the middle of the ultraviolet region of the spectrum.

Spectrum of Electromagnetic Radiation RegionWavelength (Angstroms) Wavelength (centimeters) Frequency (Hz) Energy (eV) Radio> 10 9 > 10< 3 x 10 9 < Microwave x x Infrared x x x Visible x x x x Ultraviolet x x x X-Rays x x Gamma Rays< 0.1< > 3 x > 10 5

The Bohr Ring Atom n = 3 n = 4 n = 2 n = 1

Ionization Energy ■Amount of energy required to remove an electron from the ground state of a gaseous atom or ion. –First ionization energy is that energy required to remove first electron. –Second ionization energy is that energy required to remove second electron, etc.

Ionization Energy ■It requires more energy to remove each successive electron. ■When all valence electrons have been removed, the ionization energy shows a HUGE increase.

Electronegatvity ■Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. ■The Pauling scale is the most commonly used. –Fluorine (the most electronegative element) is assigned a value of 4.0 –Values range down to cesium and francium which are the least electronegative at 0.7.

Electron Affinity ■Electron affinity is defined as the change in energy of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. ■The neutral atom's likelihood of gaining an electron