Electrons In Atoms

1. Crest2. Trough3. Amplitude – half the height4. Wavelength – distance from one point on

one wave to the same point on an adjacent wave

5. Frequency – Number of times a wave passes a point in one second (Hertz)

Waves

Electrons In Atoms

• Frequency & Wavelength –

• Frequency & Energy –

• Wavelength & Energy –

• Amplitude & Energy -

Waves

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

•How many complete waves are shown above?•What is the wavelength of light shown above?

Electrons In Atoms

Blu-Ray = 405 nanometers (blue light)

DVD = 650 nanometers (red light)

a. Calculate the number of wavelengths for each wave shown to the left.

b. Calculate the wavelength of each wave.

c. 1 nm = 1 X 10-9 m. Convert each wavelength to nm.

d. Which of the waves would be in the visible range?

Electrons In Atoms

1. All electromagnetic radiation moves at speed of light (186,000 mi/s or 3 X 108 m/s)

2. All EM radiation is a form of light

3. Visible light = 400 nm to 700 nm

violet red

Light

Light

Radio Radar Micro IR Visible Light

UV X-rays

Gamma

The Electromagnetic Spectrum

Safe radiation (non-ionizing) Dangerous (ionizing)

Produced by nuclear decay

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

MicrowavesTraditional Heat – increase translational motion of waterMicrowaves – increase rotational motion of water

Electrons In Atoms

Traditional Heat Microwaves

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Electrons In AtomsLight

Electrons In Atoms

Electrons In Atoms

c =

c = speed of light (3 X 108 m/s)

= wavelength (meters) = frequency (Hz or s-1)

Important conversion 1 nm = 1 X 10-9 m

Electrons In Atoms

Calculate the wavelength of a 60 Hz EM wave

5 X 106 m

Electrons In Atoms

Calculate the wavelength of a 98.5 MHz FM radio station

3.05 m

Electrons In Atoms

Calculate the frequency of 500 nm blue light.

6 X 1014 s-1

Electrons In Atoms

6. Wave-Particle Duality

a. light can be viewed as both a wave and a particle

b. Max Planck/Einstein ~1910

c. Photon – has no mass, only energy

Light

Electrons In AtomsLight

Electrons In Atoms

E = h(for one photon)

E = Energy (J)

h = 6.63 X 10-34 J s (Planck’s constant)

= frequency (Hz)

Electrons In Atoms

Calculate the energy of laser light with a frequency of 4.69 X 1014 s-1 .

Ans: 3.11 X 10-19 J (This is for one photon)

Electrons In Atoms

Calculate the energy of a photon of wavelength 600 nm.

ANS:3.3 X 10-19 J

Calculate the energy of a photon of wavelength 450 nm (blue light).

Ans: 4.42 X 10-19 J (This is for one photon)

A single photon has an energy of 3.616 X 10-19 J.

a. Calculate the frequency of the photon.

b.Calculate the wavelength of a photon in meters

c. Calculate the wavelength of a photon in nanometers.

d.Is this photon in the visible range?

e. What range of the spectrum would you expect a photon of 800 nm to be?

f. Calculate the energy for one mole of photons with individual energies of 3.616 X 10-19 J.

a. 5.45 X 1014 Hz

b. 5.50 X 10-7 m

c. 550 nm

d. Yes

e. IR

f. 3.616 X 10-19 J X 6.02 X 1023 photons

1 photon 1 mole

=2.18 X 105 J/mol

Electrons In Atoms

My = 8.1 X 10-36 m at 3 mph

Newtonian Mechanics Quantum Mechanics

Everything is a particle Everything is both a wave and a particle

Large objects (dust, people, baseballs, etc..)

Photons, electrons, atoms, molecules

All values are allowed Quantized – only certain values allowed

Predictable Probabilistic

Electrons In Atoms

1. Neils Bohr Planetary Model

2. Studying line spectra of elements

– Only certain lines are present (quantized)

– Not a rainbow– Spectra are a fingerprint for

atoms/molecules (Astronomy)

Bohr Model

Electrons In Atoms

Electrons In Atoms

Quantized – only certain orbits exist (rest is forbidden zone)

4. Ways to make something glow

Bohr Model

Photon Absorption Collision-Glow in the dark -Heat

-Electricity-Chemical Reaction

Photon Absorption Collision

Electrons In Atoms

Electrons In Atoms

A single photon has a wavelength of 150 nm.a.Calculate the wavelength of a photon in meters (1.50 X 10-7 m)b.Calculate the frequency of the photon. (2.0 X 1015 Hz)c.Calculate the energy of the photon. (1.33 X 10-18 J)d.Is this photon in the visible range?e.Calculate the energy for one mole of these photons. (8.01 X 105 J)

Electrons In Atoms

Electron as a particle

Heisenberg Uncertainty Principle – can never know both the position and velocity of an electron at the same time

Quantum Mechanical Model

Electrons In Atoms

a. Electron cloud b. Electron moves randomly (not like a planet)c. Orbital – region of 90% probability

Electrons In Atoms

nucleus

Random electron

cloud

Electrons In Atoms

Electron as Wave

Schrodinger Wave Equation (1926) – treats electron solely as a wave

Quantum Mechanical Model

Electrons In Atoms

Electrons In Atoms

Result One - Explains the forbidden zone (waves do not match)

Quantum Mechanical Model

Electrons In Atoms

Quantum Mechanical Model

Waves match here (get a clear note)

Waves do not match here

(get a bad note, forbidden zone)

Electrons In Atoms

Result Two

Orbits are not circular

Quantum Mechanical Model

Electrons In AtomsBohr Model Heisenberg

(Particle)

Schrodinger

(Wave)

Explains line spectra

Planetary model

Electron moves randomly

Electron cloud

Explains f. zone

Shapes of orbits

1. Draw an s, p and d orbital

2. How many electrons can be placed in an s orbital?

3. How many electrons can be placed in an p orbital? In a p suborbital?

4. How many electrons can be placed in an d orbital? In a d suborbital?

5. How many electrons can be placed in an f orbital? In an f suborbital?

6. How did Heisenberg consider the electron?

7. How did Schrodinger consider electron?

Electrons In Atoms

First QN – how far the electron is from the nucleus (larger the number, farther away) – Level or shell

Quantum Numbers

n = 2

n = 1

Electrons In Atoms

Second QN – the shape of the orbital

Quantum Numbers

Electrons In Atoms

Third QN – the suborbital

Orbital # suborbitals Total e-

s 0 2

p 3 (px,py,pz) 6d 5 10f 7 14

Quantum Numbers

Electrons In Atoms

Electrons In Atoms

Electrons In AtomsQuantum Mechanical Model

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Fourth QN – spin of the electron

Pauli Exclusion Principle – two electrons in the same suborbital (ex: px) must have opposite spins

+1/2 -1/2

Quantum Numbers

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Electrons In Atoms

Electron Configuration

Electrons In Atoms

1. Electron Configuration – shorthand notation to tell you the locations of all the electrons in an atom or ion

2. Notation

2p3

Orbit Shape # e-

Electron Configurations

Electrons In AtomsElectron Configurations

Electrons In Atoms

Electrons In Atoms

H

He

Li

O

Fe

S

Electron Configurations

Be V

N F

Sr Ar

P Mg

Se Kr

Which element is represented by the following electron configurations?

1s22s22p63s23p64s23d5

1s22s22p63s23p64s23d104p65s24d7

1s22s22p63s23p64s1

1s22s22p63s23p3

1s22s22p63s1

1s22s22p63s23p2

1s22s22p63s23p64s23d104p6

Electrons In Atoms

1. Rule – Use the noble gas in the previous row2. Examples

NePRuKr

You try:

Br Ar S Ca I Xe

Noble Gas Shortcut

Br I

Ar Ca

S Xe

Electrons In AtomsExceptions

• Mostly with transition metal elements

• There is a special stability to filled and half-filled orbitals

Element Actual configuration Instead of

Cr [Ar]4s13d5 [Ar]4s23d4

Mo [Kr]5s14d5 [Kr]5s24d4

Cu [ Ar]4s13d10 [Ar]4s23d9

Ag [Kr]5s14d10 [Kr]5s24d9

Electrons In Atoms

p e e- configuration

Sr

Sr+

Sr2+

Ions

Electrons In Atoms

p e e- configuration

SS1-

S2-

Br1-

Ba2+

Ions

p e E configuration

Na+

P3+

P3-

Sn2+

B3+

Se2-

Cl-

As3-

F1-

Ca2+

N2+

S2-

As3-

Electrons In Atoms

1. Outershell Electrons

2. Only Electrons involved in bonding

3. H2O example

4. Many elements want 8 valence electrons (Noble Gas Configuration)- Full Octet

Valence Electrons

Electrons In Atoms

Electrons In Atoms

e config #ve Lewis dot

HLiBeMg

Valence Electrons

Electrons In Atoms

e config #veLdot

OSCGe

Valence Electrons

Electrons In Atoms

e config Ldot

NaNa+

MgMg+

Mg+2

Valence Electrons

Electrons In Atomse config Ldot

B

B1+

B2+

B3+

Te

Te1-

Te2-

Valence Electrons

Electrons In Atoms

e config Ldot

Be

Be+

Be2+

Valence Electrons

Electrons In Atoms

e config #ve Ldot

ClCl-

OO1-

O2-

Valence Electrons

Electrons In Atoms

Gr I Gr II Gr III Gr IV Gr V Gr VI Gr VII

Gr VIII

1

v. e-

2

v. e-

3

v. e-

4

v. e-

5

v. e-

6

v. e-

7

v. e-

8

v. e-

+1 +2 +3 No charg

e

-3 -2 -1 0

Electrons In AtomsPeriodic Properties

Periodic Properties – Properties that depend on an element’s position on the table

Ex: Groups

H, Li, & Na all form similar oxides

(H2O, Li2O, Na2O)

Location gives you A LOT of information

Electrons In Atoms

Electrons In AtomsSize of Atoms

Atomic Radius

1. Measured in

picometers (1pm = 1 X 10-12 m) or Angstroms (1 Å = 100 pm)

2. Average radius ~100 pm (1 Å)

Electrons In Atoms

Electrons In AtomsSize of Atoms

3. Example: Bromine 1.14 Å

1.14 Å X 100 pm = 114 pm

1 Å

Electrons In Atoms

Effective Nuclear Charge

Charge from nucleus that

is not blocked (shielded)

by core electrons

Zeff = Z-S

Z = # protons

S = # core electron

Electrons In Atoms

What is the Zeff for Lithium (1s22s1)?

Electrons In Atoms

What is the Zeff for Fluorine ([He]2s22p5)?

e- configuration Zeff

S

O

P

O2-

Mg2+

K+

Electrons In AtomsSize of Atoms

Down a group

e- config Levels Zeff

H

Li

Na

Electrons In AtomsSize of Atoms

Down a group – atoms get larger, more levels

e- config Levels Zeff

H

Li

Na

Electrons In AtomsSize of Atoms

Electrons In AtomsSize of Atoms

Across a period – atoms get smaller. Same levels, greater Zeff (nucleus pulls electrons closer)

Li F

E config

levels

Zeff

Electrons In AtomsSize of Atoms

Electrons In AtomsSize of Atoms

Si Cl

E config

levels

Zeff

Electrons In AtomsSize of Ions

A. Positive Ions

1. Example:

Mg Mg+ Mg2+

E config

levels

Zeff

electrons

Electrons In AtomsSize of Ions

Electrons In AtomsSize of Ions

Positive ions always smaller– Fewer electrons to control– Less e- to e- repulsion

Electrons In Atoms

Mg Mg+ Mg2+

E config

levels

Zeff

electrons

Electrons In AtomsSize of Ions

B. Negative Ions

1. Example:

O O2-

E config

levels

Zeff

electrons

Electrons In AtomsSize of Ions

Electrons In AtomsSize of Ions

Negative ions always larger– More electrons to control– More e- to e- repulsion

a. Rank the three elements from smallest to largest

b.Which factor is most important in comparing Mg and Sr, levels or Zeff? Explain.

c. Which factor is most important in comparing Mg and S, levels or Zeff? Explain.

d.Which would be larger, S or S2-? Explain.

Mg S SrElectron Config.

Levels

Zeff

Electrons In AtomsMore levels

Greater Zeff

(same levels, greater Zeff smaller)

IonsPositive = Smaller(less electron repulsion)

Negative = Larger (more electron repulsion)

If same

If same

Size ReviewWhich is larger and why?Li or K

S or S2+

Mg or S

O or Te

Size ReviewWhich is larger and why?Cl or Al

B or B+

Al or In

B or B-

Electrons In AtomsSize Review

KurveballK or K+

Electrons In AtomsIonization Energy

A.Ionization energy – The energy needed to remove an electron from an atom

Na Na+ + e-

Electrons In Atoms

A low energy photon will excite an electron

A high energy photon may ionize an atom (completely remove the electron)

He

Ne

Ar

KLi Na

H

Electrons In AtomsIonization Energy

B. Across a period – Ionization Energy INCREASES

1. Harder to remove an electron (atom is smaller, holds e- more tightly)

2. Examples:

Li (520 kJ/mol) F (1681)

Electrons In Atoms

Electrons In AtomsIonization Energy

C. Down a group–Ionization Energy DECREASES1. Easier to remove an electron (atom is larger, holds e- more loosely)2. Examples:

Li (520 kJ/mol)

Na (496 kJ/mol)

K (419 kJ/mol)

Electrons In AtomsIonization Energy

Which has the higher Ionization Energy and why?

C or O

Na or Cl

C or Sn

Mg or Ra

Multiple Ionization Energy

Multiple Ionizations - Removing more than one electron1st Mg Mg+ + e- 738 kJ/mol2nd Mg+ Mg2+ + e- 1450 kJ/mol3rd Mg2+ Mg3+ + e- 7732 kJ/mol

There is a large jump once you reach Noble Gas

Configuration (Fewer levels, spike in Zeff)

Multiple Ionization Energy

Multiple Ionization Energy

1st Al Al + + e- 577 kJ/mol

2nd Al + Al 2+ + e- 1816 kJ/mol

3rd Al 2+ Al 3+ + e- 2744 kJ/mol

4th Al3+ Al4+ + e- 11580 kJ/mol

Multiple Ionization Energy

Examples:

a. Where will the large jump in I.E. occur for:

Be B P

b. Element X has a large jump between its 4th and 5th I.E. To what group does it

belong?

Size ReviewWhich is larger and why?N or N3-

C or F

Sr or Be

O or O2-

Size ReviewWhich has the larger ionization

energy and why?P or P3+

B or F

Ba or Be

S or Na

Electrons In Atoms

1. Spectroscopy

2. Spec 20

a. Light Source

b. Slit

c. Prism/Monochromator

d. Sample

e. Light Meter (PMT)

Light

Emission Spectrum of Air

Wavelength(nm) Wavelength(m) Frequency (Hz) Energy (J)

550 5.50 X 10-7 5.45 X 1014 3.61 X 10-19

120 1.20 X 10-7 2.50 X 1015 1.66 X 10-18

0.115 1.15 X 10-10 2.61 X 1018 1.73 X 10-15

1490 1.49 X 10-6 2.01 X 1014 1.33 X 10-19

405 4.05 X 10-7 7.41 X 1014 4.91 X 10-19

650 6.50 X 10-7 4.62 X 1014 3.06 X 10-19

800 8.00 X 10-7 3.75 X 1014 2.49 X 10-19

14.9 1.49 X 10-8 2.01 X 1016 1.33 X 10-17

2a. 1 X 10-7 m

b.3 X 1015 Hz

c. 1.99 X 10-18 J

d.400-700 nm

e. UV

3a. 6 X 10-7 m

b. 600 nm

c. 3.31 X 10-19 J

d.Red

e. Longer

Page 231 “Assessing”

8-2 a

Orbital

s, p, d, f

spherical

p-orbital

3 subshells

p orbitals

8-3 a) 18 b) 3 c) 2, 6, 10 d) 0,3,5

8-1 UV light has higher energy (shorter wavelength)

8-2 n=9 to n=1 will have a shorter wavelength

8-3 n=3 to n=1 will have a shorter wavelength

8-4 Excited state, Li is only in the second period

8-5 1p and 3f

8-6 2d does not exist

Li 1s22s1

Br 1s22s22p63s2 3p64s23d104p5

In 1s22s22p63s2 3p64s23d104p65s2 4d105p1

Ne 1s22s22p6

N 1s22s22p3

Ca 1s22s22p63s2 3p64s2

Al 1s22s22p63s2 3p1

S 1s22s22p63s2 3p4

Kr 1s22s22p63s2 3p64s23d104p6

Zr 1s22s22p63s2 3p64s23d104p65s2 4d2

Fe 1s22s22p63s2 3p64s23d6

C 1s22s22p2

Ar 1s22s22p63s2 3p6

Pd 1s22s22p63s2 3p64s23d104p65s2 4d8

He 1s2

O 1s22s22p4

Ti 1s22s22p63s2 3p64s23d2

Na 1s22s22p63s1

Mg 1s22s22p63s2

Si 1s22s22p63s2 3p2

C 1s22s22p2

Ne [He]2s22p6 S [Ne]3s23p4

Si [Ne]3s23p2 In [Kr]5s24d105p1

Sr [Kr]5s2 K [Ar]4s1

Fe [Ar]4s23d6 Cu [Ar]4s23d9

Te [Kr]5s24d105p4

P [Ne]3s23p3

N [He]2s22p3

Ni [Ar]4s23d8

Br [Ar]4s23d104p5

Be [He]2s2

[Ne]3s2 Mg

[Ar]4s23d3 V

[Kr]5s24d105p5 I

[Ar]4s23d104p6 Kr

[He]2s22p6 Ne

[Ne]3s23p5 Cl

O [He]2s22p4 Al [Ne]3s23p1

O1- [He]2s22p5 Al+ [Ne]3s2

O2- [He]2s22p6 Al2+ [Ne]3s1

Mg [Ne]3s2 Al3+ [He]2s22p6

Mg1+ [Ne]3s1 Cl [Ne]3s23p5

Mg2+ [He]2s22p6 Cl1- [Ne]3s23p6

N [He]2s22p3 Cl3+ [Ne]3s23p2

N3- [He]2s22p6

N3+ [He]2s2

N5+ 1s2

Electrons In Atoms4. Excited state, can emit a photon

6. 2d does not exist (d’s start with 3d)

7. Area of space where an electron is likely to be found

10.4 lobes (eggs), 4p has only 2 eggs

68. a) Tl b) Y c) Ce d) As

70. 141 pm = Sn 180 pm = Tl

Electrons In Atoms1. Ba(NO3)2

2. N2O4

3. Fe2(SO4)3

4. copper(II) chloride

5. nitrogren trihydride

6. Aluminum hydroxide

Electrons In Atoms2 1,13 1,2 2,14 1,3 3,1 2,25 1,4 4,1 2,3 3,26 1,5 5,1 2,4 4,2 3,37 1,6 6,1 2,5 5,2 4,3 3,48 2,6 6,2 3,5 5,3 4,49 3,6 6,3 4,5 5,4104,6 6,4 5,511 5,6 6,5126,6

67 a) As b) Ru c) Ba d) I

68 a) Tlb) Y c) Ce d) As

69 Cr = 117 pm, Nb = 134 pm

70 Sn = 141 pm, Tl = 180

71 a) V b) Cl c) Mg d) Fe e) B

Ca – More levels

Br- - Same levels and Zeff, more e- to control

Mg - Same levels, lower Zeff

Sb - More levels

Li – More levels

Sn – More levels

F – Smaller atom (same levels, higher Zeff)

C – Smaller atom (fewer levels)

Mg+ - Smaller atom (same levels, fewer electrons)

S - Smaller atom (same levels, higher Zeff)

Al3+ – Smaller atom (fewer levels)

Sr More levels

Sr Same levels, Sr has a lower Zeff

Sn Same levels, same Zeff, Sn has more e to e

repulsion

Te2- Same levels, same Zeff, Te2- has more e to e

repulsion

Fr More levels

Al2+ More levels

K Smaller atom, holds electrons more tightly

Cl Smaller atom, holds electrons more tightly

Ba2+ Smaller atom, holds electrons more tightly

Al Between 3rd and 4th

Rb Between 1st and 2nd

Ra Between 2nd and 3rd

Answers to Review Test1 C 11 D

2 B 12 B

3 A 13 A

4 B 14 C

5 A 15 D

6 D 16 E

7 B 17 D

8 A 18 C

9 C 19 B

10 B 20 D

E config L. Dot

S

S1-

S2-

Na+

Mg2+