1. Notes CH 5 Electron Configurations
Chemistry Sra. Bartlett U5 Electrons in Atoms
Notes CH 5 Electron Configurations
telling electrons where they can go!!

2. Electrons.. Where are they?
Chemistry Sra. Bartlett U5 Electrons in Atoms
Electrons.. Where are they?
And why do we need to know?
The chemical behavior of an element is determined by the number of electrons and how they are arranged.

3. Chemistry Sra. Bartlett U5 Electrons in Atoms
Bohr’s model
Helped explain why elements give off certain colors of light (excited electrons jumping to lower energy levels)
Electrons travel in specific energy “orbits” but not in between them.
3rd
Electron can be here
2nd
1st
But not here

4. Review…Bohr’s model of the atom
Chemistry Sra. Bartlett U5 Electrons in Atoms
Review…Bohr’s model of the atom
Each level has a certain number of e-
1st = 2
2nd = 8
3rd = 18 (or 8)
4th = 32 (or 18 or 8)
5th = 32 (or 18 or 8)
6th = 18 (or 8)
7th = 8
**Note= last level cannot have more than 8 valence e-
Energy levels
nucleus

5. Bohr models of various atoms.
Chemistry Sra. Bartlett U5 Electrons in Atoms
Bohr models of various atoms.
Draw (or write) the Bohr sequence for Calcium (20)
Give the # of valence electrons (last level)
Tell if will lose e- (like metals, have less than 4) or gain e- (like non-metals, have more than 4) or metalloids (either gain or lose)
Give the isotope symbol

6. Bohr models of various atoms.
Chemistry Sra. Bartlett U5 Electrons in Atoms
Bohr models of various atoms.
Draw (or write) the Bohr sequence for Bromine
Give the # of valence electrons (last level)
Tell if will lose e- (like metals, have less than 4) or gain e- (like non-metals, have more than 4) or metalloids (either gain or lose)
Give the isotope symbol

7. Chemistry Sra. Bartlett U5 Electrons in Atoms
Example
For all the element Bromine (35):
1) Draw (or write) the Bohr sequence
2) Give the # of valence electrons
3) Tell if will lose e- (like metals) or gain e- (like non-metals)
4) Give the ion symbol and charge
2 – 8 – 7
Will gain one electron
80 35 Br -1

8. Chemistry Sra. Bartlett U5 Electrons in Atoms
Question
Why do elements give off different colors of light when heated? (need to know for LAB on Friday)
Some of the electrons (ground state) gain enough energy from the heat to jump up to a higher energy level (excited state). They are unstable here so they jump back to a lower level and give off the energy gained as photons. The photon’s energy determines the frequency (and color) of light.

9. Flame tests and Spectra
Chemistry Sra. Bartlett U5 Electrons in Atoms
Flame tests and Spectra
Each element has a characteristic pattern of light that it emits.
This can be used as a “fingerprint” for identification.

10. Chemistry Sra. Bartlett U5 Electrons in Atoms
Niels Bohr’s Atomic model Yes! It’s Bohring!

11. Assignment = Simple atomic models
a. Bohr’s model
b. isotope symbol
c. charge
For these elements: S, As, Sr, Ar, Cl, Ag
2. Pg 145 # 10, (show details for calculations)

12. Modern views of the Atom
Chemistry Sra. Bartlett U5 Electrons in Atoms
Modern views of the Atom
Electrons can act as particles and sometimes as waves (dual nature)
Electrons travel in paths that look like clouds. The size and shape of these depend on how much energy the electrons have.
The 4 quantum numbers describe the location of the electrons:
Principal QN (symbol “n”) refers to the number of energy levels and indicates the relative size and energies in the atomic orbitals.

13. Chemistry Sra. Bartlett U5 Electrons in Atoms
Secondary or angular QN (symbol “l” ) indicates the sublevel (s, p, d, or f)
Magnetic QN (symbol “m”) indicates the orbital the electron is in (px, py or pz)
Spin QN (symbol “s” ) indicates the direction the electron is spinning (left or right)
There are 7 energy levels divided into different sublevels which are divided into orbitals.
An orbital is the space where two electrons travel. They have the shape of the sublevel but different orientations.
Sublevels:
s = 2 e- max p = 6 e- d = 10 e- f = 14 e-

14. Chemistry Sra. Bartlett U5 Electrons in Atoms
“p” =

15. Chemistry Sra. Bartlett U5 Electrons in Atoms
Shape of d

16. Chemistry Sra. Bartlett U5 Electrons in Atoms
Shape of f

17. Chemistry Sra. Bartlett U5 Electrons in Atoms
Mind Blowing!!
Just read
Just imagine an atom with for example 92 electrons like Uranium. All are whizzing around the nucleus at the speed of light in different shaped paths.
Video orbitals!

18. Electron configuration (long form)
Chemistry Sra. Bartlett U5 Electrons in Atoms
Electron configuration (long form)
This gives MORE information about predicting properties.
The placement of an elements electrons is written as:
4th Energy level
6 electrons
4p6
These add up to total # of e-
Sublevel p
1s2, 2s2, 2p6, 3s2, 3p6
How many total electrons?
What element is it?

19. Chemistry Sra. Bartlett U5 Electrons in Atoms
There are rules!
Aufbau rule: Electrons occupy the lowest energy orbitals first.
Hund’s rule: States that single electrons must occupy separate orbitals before pairing up.
Pauli Exclusion Principle: No two electrons in an atom have all 4 quantum numbers the same. One quantum number must be different. Aka  SPIN!

20. Chemistry Sra. Bartlett U5 Electrons in Atoms
The “Arrow” Diagram
Electrons arrange themselves in orbitals of increasing energy.
Examples: N Al K Br Ag
This is on page 160.
s = 2 p = 6 d= 10 f = 14

21. Chemistry Sra. Bartlett U5 Electrons in Atoms
Take sulfur for example. It has an atomic number of 16, so it has 16 electrons. Let’s put these in order.
1s2, 2s2, 2p6, 3s2, 3p4
Valence e-? _____ on level ____
How many e- lost/gained? _______
Charge of ion? _______
Check it! it should be in group 6 and on period 3 ……is it?

22. Chemistry Sra. Bartlett U5 Electrons in Atoms
Practice
Write the electron configuration (long form) for:
Arsenic ____ electrons
And for arsenic’s ion? (As3-)
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p3

23. Chemistry Sra. Bartlett U5 Electrons in Atoms
Practice
Write the electron configuration (long form) for:
Silver ____ electrons
And for silver ion?
Hint: it loses one e-)
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6 , 5s2 , 4d9

24. HW
pg. 160 #21 & 22 and WS

25. Chemistry Sra. Bartlett U5 Electrons in Atoms
Bellringer
Turn in HW pg 160 (21, 22)
A) Write the long-form electron configuration for V (23)
B) tell how many valence e- it has
C) give the ionic charge
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d3 ; 2; 2+

26. Chemistry Sra. Bartlett U5 Electrons in Atoms
Bellringer 2
Which QN symbol means “main energy level”?
Which 4 symbols means “sublevel”?
Write the long configuration for Se (34)
How many valence electrons are there?
What will the charge of the ion be? n
s, p, d, f
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p4 6 2-

27. Electron configuration Shorthand version (Noble gas version)
Chemistry Sra. Bartlett U5 Electrons in Atoms
Electron configuration Shorthand version (Noble gas version)
Ex Silver = [1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6 ], 5s2 , 4d9
Take the previous Noble Gas and substitute
[Kr], 5s2 , 4d9
Or do directly from PT……

28. Chemistry Sra. Bartlett U5 Electrons in Atoms
Copy or memorize… or Google
→ ← p →
“f” before “d” d (n-1) and f (n-2)

29. Chemistry Sra. Bartlett U5 Electrons in Atoms
More….
Oxygen
And O2- ??
Arsenic
Aluminum
And Al3+ ??
Europium

30. Chemistry Sra. Bartlett U5 Electrons in Atoms
More Practice
Fe 3+
F1-
Na1+
N 3-

31. Chemistry Sra. Bartlett U5 Electrons in Atoms
Rules? …..What rules?
Electrons can behave as a particle but also have wavelike behavior (dual-nature by DeBroglie)
Electrons will be in the lowest available energy position first. (Aufbau rule)
Electrons will be in separate orbitals (same energy) before pairing up. (Hund’s rule)
Electrons will orient themselves to have opposite spins if in same orbital. (Pauli rule)
What??? Let’s try applying this…..

32. Chemistry Sra. Bartlett U5 Electrons in Atoms
Orbital diagrams
We use boxes to indicate
the orbitals
And arrows to indicate each electron 1s 2s 2p 3s 4d

33. Chemistry Sra. Bartlett U5 Electrons in Atoms
Practice
Let’s do oxygen (8e-)
So…it has 2 unpaired electrons to use for bonding with other elements.
And now aluminum (13 e-) 1s 2s 2p 3s 3p 1s 2p 3s 3p 2s

34. Chemistry Sra. Bartlett U5 Electrons in Atoms
More
Let’s do Neon (10 e-)
And now chlorine (18 e-) 1s 2s 2p 3s 3p 1s 2p 3s 3p 2s

35. Chemistry Sra. Bartlett U5 Electrons in Atoms
And
Vanadium
Selenium

36. Chemistry Sra. Bartlett U5 Electrons in Atoms
Bellringer
Turn in Homework
What is the long form electron configuration for sulfur? See pg 160
How many valence electrons does it have and on what level?
How many e- does it need to have a complete valence level?
What is the short form and orbital diagram for Te (52)?
What is wrong with this? [Ar] 4s2, 3d6 , 4p3

37. Practice Pd Ge Pb Bohr model long form Short form Orbital diagram
Valence e-
Pd Ge Pb

38. Homework At (85) K(19) Se (34) P(15) Bohr model long form Short form
Orbital diagram
Valence e-
At (85) K(19) Se (34) P(15)

39. Chemistry Sra. Bartlett U5 Electrons in Atoms
Video

40. Electron Dot Diagrams
Only show valence electrons
Examples:

41. Chemistry Sra. Bartlett U5 Electrons in Atoms
Assignment
Pg 167 (Glencoe)
# 81, 85, 86, 87, 90

42. Chemistry Sra. Bartlett U5 Electrons in Atoms
To turn in!
Write the:
a) short electron configuration.
b) # of valence e
c) # e- lost/gained
d) charge of ion
iodine 5. helium
hafnium 6. boron
francium 7. yttrium
xenon 8. tin

43. Chemistry Sra. Bartlett U5 Electrons in Atoms
Exit slip
For the element Phosphorous (P) and
Bromine (Br)
Write the:
a) short electron configuration.
b) # of valence e
c) # e- lost/gained
d) charge of ion
e) orbital diagram

44. Chemistry Sra. Bartlett U5 Electrons in Atoms
Bellringer
What is the long form electronWhich symbol means “main energy level”?
Which symbol means “sublevel”?
Which symbol means “number of electrons”?
How many valence electrons are there?
What will the charge of the ion be?
[Ar] 4s2, 3d10 , 4p3
3 or 4
s, p or d
2, 3 or 10 5 3-

45. Chemistry Sra. Bartlett U5 Electrons in Atoms
Bellringer
What symbol is used in orbital diagrams to show one electron?
What rule says that electrons will occupy the lowest energy orbitals first?
Who first stated that electrons can behave both as a particle and as a wave?
What do we call the distance on a wave for a complete cycle?
What do we call the height (energy) of a wave?
An arrow
Aufbau
DeBroglie
Wavelength
Amplitude

46. Chemistry Sra. Bartlett U5 Electrons in Atoms
To turn in!
Write the:
a) Bohr sequence (ex 2-8-3)
b) long electron configuration.
c) # of valence e
d) # e- lost/gained, charge of ion
Palladium 5. Argon
Indium 6. Molybdenum
Gadolinium 7. Polonium
Dysprosium 8. Radium

47. EMR (electromagnetic radiation)
Chemistry Sra. Bartlett U5 Electrons in Atoms
EMR (electromagnetic radiation)
All wavelengths = from gamma rays (very short=high energy) to radio and TV (long=low energy).
All types of EMR travel at the speed of light
Are emitted when excited electrons jump to lower energy levels.
A “piece” or quantum of EMR is called a photon.

48. Chemistry Sra. Bartlett U5 Electrons in Atoms
Review EMR waves
or crests
A Solving problems Show all your work, write the equation and be sure to indicate your units
c= v and E­photon = h v
speed of light is c=3.00 x 108 m/s
Planck’s constant is h = x 10-34J s
What is the wavelength of electromagnetic radiation with a frequency of 8.77 x 1014 Hz?
What is the frequency of light that has a wavelength of nm?

49. More
Calculate the frequency for yellow light See handout
600 nm = 600 x -9 m
Calculate the frequency for a bar-code laser.
660 nm = 660 x m
Calculate the energy for an X-ray photon (3.88 x Hz)
5.00 x /s
4.55 x /s
2.57 x J