PP 13: Electronic Structure
Drill: Calculate the volume of O2 released at 127oC under 83.1 kPa when 3.2 mg Fe2O3 is decomposed.
Review the last test
Electronic Structure:
Electrons do not orbit nucleii, but move randomly in space around the nucleus
Orbital: The space in which the electrons (e-) are likely to be found.
Max 2 e- per orbital
Electron configuration: A description of the electrons in an atom
Rule of Electron configuration (EC):
•
•
•
•
•
•
Number: energy level (row #)
Letter: energy sublevel (area)
Superscript: # of e- in sublevel
d electrons: 1 level < row #
f electrons: 2 levels < row #
Include all filled sublevels
EC consist of a number, a letter, & a superscript
EC consist of all filled sublevels, as well as, the
final partially filled sublevel
Energy Levels: (Number)
•
•
•
Corresponds to row #
1-7
Related to size
Energy Sublevels: (Letter)
•
•
•
Corresponds to an area on the periodic table
= nodes in orbitals
s, p, d, f
• s - electrons
• Columns 1A & 2A
• Spherical orbitals
• p – electrons
• Col. 3A - 8A or 13 - 18
• Dumbbell shaped orbital
• 3 orbitals per sublevel
• 1 node
• d – electrons
• Cols 3B - 2B or 3 - 12
• Transition area (2 nodes)
• Double dumbbell shaped
• 5 orbitals in sublevel
• d – electrons are always one energy level less than the row number
• f – electrons
• Lower removed area
• Triple dumbbell shaped
• 7 orbitals per sublevel
• 3 nodes
• F – electrons are always two energy levels less than the row number
Drill: Calculate the volume of O2 at 127oC under 83.1 kPa required to burn 6.20 g of C2H6O2:
Degenerate Orbitals: Orbitals at the same energy level.
3 p orbitals, 5 d orbitals, & 7 f orbitals:
each set has degenerate orbitals
Use the Periodic Table & chart below to demonstrate Electron Configuration:
5p __ __ __
4d __ __ __ __ __
5s __
4p __ __ __
3d __ __ __ __ __
4s __
3p __ __ __
3s __
2p __ __ __
2s __
1s __
Drill: List, describe, & identify the area of the Periodic Table for each type of orbital.
Electron Configuration (EC):
•
•
Write the notation for each energy sublevel, from the lowest energy level to the highest
energy level, filled with e-s within an atom.
EC notation consist of a number, a letter & a superscript
• Number-Energy level or row number
• Letter-Energy sublevel or area of the periodic table
• Superscript-# of e-s in sublevel
• Exceptions:
• d e-s are 1 level < row number
• f e-s are 2 levels < row number
Demonstration of Electron Configuration:
Write the Electron Configuration for Os-76
Os- 1s22s22p63s23p64s23d104p65s24d105p66s24f145d6
The superscripts should add up to 76.
Add the superscripts starting with the same 1st number to get the # of e-s in each energy level.
Practice for Electron Configuration:
•
•
•
•
•
•
•
•
F-9
Rb-37
Tc-43
As-33
Ba-56
Hg-80
I-53
U-92
d-Block Inversion: Describe the consistent inversion in columns 6B & 1B in the d-block
Chromium & Copper are Kinky
• 4s23d1
4s23d6
• 4s23d2
4s23d7
• 4s23d3
4s23d8
• 4s13d5
4s13d10
• 4s23d5
4s23d10
One of the outermost s electrons
become a d electron in copper &
chromium columns as highlighted
in the series to the left.
4s23d4 becomes 4s13d5 &
4s23d9 becomes 4s13d10
Drill: Write the ECs for each of the following:
Gd-64
Mo-42
Ra-88
Mn-25
Practice problems: Write the ECs for each of the following:
Sn
I-1
Pt
Mn+2
Ground State: All electrons are in their lowest possible energy level
Excited State: When one or more electrons are not in their lowest possible energy levels
Valence Electrons:
•
•
Electrons in the outer most energy level
Electrons involved in chemical reactions
All Transition elements have either 1 or 2 electrons in their outermost energy level.
All inner-transition elements have two electrons in their outermost energy level
Electron Dot Diagram: (EDD)
•
•
•
•
•
Represents the valence electrons in an atom
Maximum 4 pairs drawn on an imaginary square around the symbol
The number of dots drawn around any symbol will equal the elements column number.
Transition elements have a pair of dots except when kinky when they have a single dot.
All inner transition elements have a pair of dots.
EDD Examples: The column number will be used to represent Symbol for each element.
1A
2A
3A
4A
5A
6A
Transition Dot Diagrams:
•
•
Kinky ones have a single
All the rest have a pair
Inner Transition Dot Diagrams: All have a pair of dots.
Octet Rule:
•
•
8 electrons in the outer level is stable
Elements attempt to get eight electrons in their outer level to stabilize.
Practice problems: Write the ECs & EDD for:
Zn
Au
Drill: Write the EC & EDD for:
Al+3
Fe+3
Se-34
Mo-42
Spectrum: The unique set of waves absorbed or emitted by a substance
Absorption Spectrum:
•
•
•
The unique set of wavelengths absorbed by a substance
Atomic Absorption Spectrum
Dark Line Specrtum
Emission Spectrum:
•
•
•
The unique set of wavelengths emitted by a substance
Atomic Emission Spectrum
Bright Line Spectrum
7A
8A
Spectroscopy: The study of a substance under continuous excitation energy
Wave Formula: v or c = f
•
•
•
c = speed of light
= wavelength
f = frequency
Problems: Calculate the wavelength of your favorite radio station (FM in MHz) (AM in kHz)
Plank’s Formula for the energy of a wave:
•
•
•
E = hf = hc/
E = energy
h = Plank’s Constant = 6.63 x 10-34 J*s
Problem: Calculate the energy of uv light at 221 nm:
DeBroglie’s Formula: for the duality of waves (the act like waves & particles)

= h/mv
o  = wavelenght
o h = Plank’s Constant
o m = mass
o v = velocity
Problem:



Calculate the wavelength of a 221 g baseball thrown at 15 m/s.
Calculate the energy and mass of a photon of IR light at 1.326 mm:
Calculate the mass & energy of a gamma ray with a wavelength of 221 x 10-10 nm.