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jeremy-elliott
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Topic: Modern Model of the atom - ORBTIALS
Principal Energy Levels (PEL)
• Also known as “shells”
• Can have values of 1, 2, 3, 4…..• (whole numbers)• Electrons in PEL’s with greater numbers
have greater energy.
• [Similar to rows of seats in a stadium)
Sublevels• Each principle energy level is
made up of 1 or more sublevels
1st PEL = s (1 sublevel) 2nd PEL = s,p (2 sublevels)3rd PEL = s,p,d (3 sublevels)4th PEL = s,p,d,f (4 sublevels)
Orbitals
• s has 1 orbital• p has 3 orbitals • d has 5 orbitals• f has 7 orbitals
• Each sublevel contains 1 or more orbitals• Each orbital holds a max of 2 electrons
1st PEL = s (1 sublevel) = 1 orbital (____ electrons)2nd PEL = s,p (2 sublevels) = 4 orbtials (____ electrons)3rd PEL = s,p,d (3 sublevels) = 9 orbitals (___ electrons)4th PEL = s,p,d,f (4 sublevels) = 16 orbitals (____ e-)
2
8
18
32
Memorize• S P D F• 1 3 5 7• 2e- 6e- 10e- 14e-
s
p
d
f
*Each orbital holds a max of 2 electrons
sublevels
# of orbitals
Max # of electrons
Orbitals• s orbital: sphere
• p orbital: dumbell
• d orbital: 4 clovers,1 double ended pacifier
• f orbital: funky!! Flowers? You describe!
• http://www.d.umn.edu/~pkiprof/ChemWebV2/AOs/ao4.html
Bohr Model vs. Modern Model
• Electron = particle• Orbit• Holds 2n2
electrons• Circular • Each orbit has
specific energy• Exact location
• Electron = Wave• Orbital• Holds 2 electrons• Not necessarily circular• Each orbital has
specific energy• Probable location
(wave mechanical model)
Electron configurations• Adding electrons to atoms
so that the electrons are in the lowest energy levels – most stable or ground state configuration
• Start with 1s, then work upward in order of increasing energy.
• Use Aufbau rule.
Aufbau
1s2
2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10 4f14
5s2 5p6 5d10 5f14
6s2 6p6 6d10
7s2 7p6 7d10
1s2
2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10 4f14
5s2 5p6 5d10 5f14
6s2 6p6 6d10
7s2 7p6 7d10
He
C
Mg
Zn
1s2
1s22s22p2
1s22s22p63s2
1s22s22p63s23p6 4s23d10
He
C
Mg
Zn
1s2
1s22s22p2
1s22s22p63s2
1s22s22p63s23p6 4s23d10
From these modern configurations, we can figure out Bohr Configurations
All you have to do is add up the electrons in each shell (PEL)
1 = 2
2
1 = 2 2 = 2+2
2 – 4
1 = 2 2 = 2+6 3 = 2
2 – 8 – 2
1 = 2 2 = 2+6 3 = 2+6+10 4=2
2 – 8 – 18 – 2
Orbital Diagrams
Shows the orbital the electron is located in
Shows the spin – they have to be opposite!(spin up or spin down)
Hund’s Rule• Maximum multiplicity – most e- with
same spin.– So, Fill up before pairing up
• 1s2 2s2 2p4
Which element?How many unpaired e-? How many PEL’s occupy?How many PEL’s are fully occupied?How many sublevels contain e-?How many sublevels full?How many orbitals contain e-?
Boron
1
2
1
3
3
2