Quantum Theory and the Organization of the Periodic Table

Quantum Theory and the Organization of the

Periodic Table

Bohr’s model has some flaws.

Bohr’s model has set tracks for electrons to travel, but in reality they were in all space almost at the same time. Like a ceiling fan rotating in three dimensions.

True Nature of Waves and Particles

Wave-Particle Duality: Light and some forms of matter (like electrons) can be viewed as both a wave as well as a particle.

Created by de Broglie

Wave-Particle Duality of Nature

Heisenberg uncertainty principle – it is impossible to know both the exact position and the exact momentum of an object at the same time.

- the more that we know of one, the less we know of the other.

- treats electrons as particles

Heisenburg uncertainty principle

- tried to treat electrons as waves.- came up with an elaborate equation to describe the location of an electron based upon certain quantum numbers

Schrodinger (ha ha, get your laughs out now….)

As a wave, typical wave properties are observed like wavelength and frequency.

Wavelength – distance from crest to crest- Measured in meters

Frequency – number of cycles in one second◦ - Measured in Hertz (Hz)

Waves

The electromagnetic spectrum shows a range of all types of electromagnetic radiation (x-rays, gamma rays, visible light, infrared, radio waves) in order of wavelength and frequency.

All types of electromagnetic radiation travels at the speed of light (c = 3.0 x 108 m/s)

Electromagnetic Spectrum

Electromagnetic Spectrum

Electromagnetic Spectrum

Shortest Longest Wavelength

Higher Energy Lower Energy

MICROWAVES

Communication

5

Highest Frequency Lowest Frequency

Wave speed = Wavelength x Frequency (m/s) (m) (Hz)

Ex. 1 What is the frequency of yellow light which has a wavelength of 580 nm?

Ex. 2 What is the wavelength of the signal from 1100AM which has a frequency of 1100 Megahertz?

Waves

What is the frequency of ultraviolet light which has a wavelength of 220nm?

What is the wavelength of gamma rays which have a frequency of 1024 Hz?

More light examples

Planck also noted that there was a relationship between the energy of light and the frequency. The higher the frequency, the greater the energy.

E = h x f◦ H = Planck’s constant (6.63 x 10 23 Joule seconds)◦ F = frequency (Hz)◦ E = Energy (Joules

Planck’s constant and equation

How much more energy is present in a gamma ray with a frequency of 1024 Hz compared to infrared rays with a frequency of 1012 Hz?

What is the frequency of electromagnetic radiation that has 65,000J of energy?

How much energy does a ray of green light have if its wavelength is 580nm?

More examples

Electromagnetic Spectrum

Emission of Light

When light is given off, the color that you see is based on the elements that are being given energy (from electricity or heat usually).

The electrons are given energy and are “excited” so they move up to the next energy level.

When the electrons return to their “ground state” they give off the energy in the form of light.

We can actually see electrons moving down in energy level through flame tests…energy given off corresponds to the color of the flame produced…

Each element has its own characteristic spectrum which can be used to identify specific elements by using a spectroscope.

Atomic Spectrum

Electromagnetic Spectrum

A quantum is a discrete particle (as opposed to a continuous wave).

Bohr explained the atomic spectrum by saying that the electrons were given energy by a photon of light (not a wave, but a “packet” of light energy)

This photon gave the electron energy as it became “excited”.

The frequency of the color given off was dependent on how much energy the electron absorbed and then emitted.

Quantum Numbers

Schrodinger proposed four different quantum numbers to describe the approximate location of an electron around a nucleus. (kind of like your house address – house number, street, city, state …)

Quantum numbers

As the principle quantum number increases, the energy level increases and the size of the atom increases.

Principle Quantum Number

Principle quantum number (n) – corresponds to energy level

- goes in order of 1,2,3,…with one being the lowest in energy

- n is also used to tell us the distance that an electron is from the nucleus.

- based on the period (or row) in periodic

table

Greatest number of electrons in each energy level = 2n2

(ex: How many e- in the 1st energy level?- the 2nd?- the 3rd?

Principle quantum number (n)

What is the maximum number of electrons that can exist in the 1st energy level (n=1)?

1 2 4 8 18

0% 0% 0%0%0%

1. 12. 23. 44. 85. 18

What is the maximum number of electrons that can exist in the 3rd energy level?

1 2 4 8 18 32

0% 0% 0%0%0%0%

1. 12. 23. 44. 85. 186. 32

What are the maximum number of electrons in the second energy level?

2 4 6 8 18 32

0% 0% 0%0%0%0%

1. 22. 43. 64. 85. 186. 32

What are the maximum number of electrons in the fourth energy level?

2 4 6 8 18 32

0% 0% 0%0%0%0%

1. 22. 43. 64. 85. 186. 32

- Sublevels - smaller energy states grouped inside a larger energy level

- Sublevels in order of increasing energy within an energy level:

s < p < d < f

Mnemonic tool: “some people don’t fart” or make up your own

Sublevels

Number of types of principal quantum

orbitals in energy level = number

Energy Level Sublevels1st energy level 1s2nd energy level 2s 2p3rd energy level 3s 3p 3d4th energy level 4s 4p 4d 4f

How many types of sublevels are in the second energy level?

1 2 3 4 5

0% 0% 0%0%0%

1. 12. 23. 34. 45. 5

How many sublevels are in the fourth energy level?

1 2 3 4 5

0% 0% 0%0%0%

1. 12. 23. 34. 45. 5

An orbital is the region that you are most likely going to find a specific electron.

Shapes of orbitals:

s – spherical p – barbell shaped (each centered on a

different axis – x,y,z)

-

Different Shapes of Sublevel Orbitals

Orbital – region occupied by one pair (2) of electrons.- s has one orbital = 1pair (2 electrons)- p has three orbitals = 3 pairs (6)- d has five orbitals = 5 pairs (10)- f has seven orbitals = 7 pairs (14)

How many sublevels are in the third energy level?

1 2 3 4 5

0% 0% 0%0%0%

1. 12. 23. 34. 45. 5

Which of the following sublevels is not present in energy level 3?

f s p d

All are prese

n...

0% 0% 0%0%0%

1. f2. s3. p4. d5. All are present

How many orbitals are in the 2p sublevel?

1 2 3 4

0% 0%0%0%

1. 12. 23. 34. 4

What is the maximum number of electrons that can fit into the 2p sublevel?

1 2 4 6 8

0% 0% 0%0%0%

1. 12. 23. 44. 65. 8

How many orbitals are in the 4d sublevel?

1 2 4 5 8 10 14

0% 0% 0% 0%0%0%0%

1. 12. 23. 44. 55. 86. 107. 14

What is the maximum number of electrons that can fit in the 5p sublevel?

2 4 6 8 10 14 32

0% 0% 0% 0%0%0%0%

1. 22. 43. 64. 85. 106. 147. 32

Describe the shape of the 4s orbital?

Spheric

al

Dumbbell s

hape...

Cube-shaped

Like a dragon

0% 0%0%0%

1. Spherical2. Dumbbell

shaped3. Cube-shaped4. Like a dragon

Overlapping occurs in the third and fourth energy level, as it takes more energy to put an electron into a “d” than an “s” or a “p”…- “d” is filled one energy level later.- “f” is filled two levels later.

These shapes are filled later because they are so complex and require additional energy to enter.

Aufbau Principle – states that electrons fill orbitals in order from the lowest to highest energy level.

Aufbau Principle

- electrons will singly fill each orbital until all orbitals have one atom before putting two electrons in one orbital.

- example: filling rooms in a hotel, seats on an airplane

Hund’s Rule

– describes difference between two electrons occupying the same orbital.

- Electrons spin in opposite directions when occupying the same orbital

- Notation for electrons with differing spins:

Pauli Exclusion Principle

We can use arrows or number and letter configurations to represent the electron configurations.

Orbital Diagram - uses arrows and boxes to represent electrons and orbitals (# of arrows should add up to atomic number)

Electron Configuration – uses orbital letters and superscripts (superscripts should add up to the total number of electrons)

Abbreviated Electron Configuration – shows the noble gas of the previous energy level and electron configuration of the top energy level.

Draw of write the following for a nitrogen (N) atom.

A. Orbital Diagram B. Electron Configuration C. Abbreviated Electron Configuration

Orbital Diagrams and Electron Configurations

Draw of write the following for a helium (He) atom.

A. Orbital Diagram B. Electron Configuration C. Abbreviated Electron Configuration

Orbital Diagrams and Electron Configurations

Draw of write the following for a nickel (Ni) atom.

A. Orbital Diagram B. Electron Configuration C. Abbreviated Electron Configuration

Orbital Diagrams and Electron Configurations

Lewis dot diagram – shows only electrons in the outermost energy levels - only looks at the “s” and the “p”

- Must show between 1-8 dots

Lewis Dot Diagrams

Lewis Dot Diagrams

GROUPS

Columns of the periodic table Atoms of elements in the same

group have the same # of valence electrons and therefore behave similarly

PERIODS•Rows of the periodic table• All elements in a period have the

their valence electrons in the same energy level.

Which of the following are in the same group?

H, H

e, C, L

i

K, Ca,

As, Br

He, N

e, Kr, A

r

B, Al, G

e, Sn

0% 0%0%0%

1. H, He, C, Li2. K, Ca, As, Br3. He, Ne, Kr, Ar4. B, Al, Ge, Sn

Which of the following are in the same period?

H, H

e, C, L

i

K, Ca,

As, Br

He, N

e, Kr, A

r

B, Al, G

e, Sn

0% 0%0%0%

1. H, He, C, Li2. K, Ca, As, Br3. He, Ne, Kr, Ar4. B, Al, Ge, Sn

Representative and Transition Elements

METALS 4 Different kinds of metals

◦ Alkali metals: soft, shiny and very reactive - Group 1: not found in nature as elements

◦ Alkaline earth-metals: less reactive- Group 2: have two valence electrons

◦ Transition Metals: many uses- Groups 3-12

NONMETALS 3 Different kinds of metals

◦ Noble Gases: mostly non-reactive, very stable- Group 8: He, Ne, Ar, Kr, Xe, Rn

◦ Halogens: very reactive, gain one electron to form a stable compound- Group 7: F, Cl, Br, I

Diatomic Gases Seven elements are called diatomic and never

exist alone in nature. Have No Fear Of Ice Cold Beans????? H2

N2

F2

O2

I2 Cl2 Br2

Magnesium is in which group?

Alkali meta

ls

Alkaline earth

...

Transition m

et...

Halogens

Noble gas

es

0% 0% 0%0%0%

1. Alkali metals2. Alkaline earth

metals3. Transition metals4. Halogens5. Noble gases

Lithium is in which group?

Alkali meta

ls

Alkaline earth

...

Transition m

et...

Halogens

Noble gas

es

0% 0% 0%0%0%

1. Alkali metals2. Alkaline earth

metals3. Transition metals4. Halogens5. Noble gases

Manganese is in which group?

Alkali meta

ls

Alkaline earth

...

Transition m

et...

Halogens

Noble gas

es

0% 0% 0%0%0%

1. Alkali metals2. Alkaline earth

metals3. Transition metals4. Halogens5. Noble gases

Krypton is in which group?

Alkali meta

ls

Alkaline earth

...

Transition m

et...

Halogens

Noble gas

es

0% 0% 0%0%0%

1. Alkali metals2. Alkaline earth

metals3. Transition metals4. Halogens5. Noble gases

The majority of the diatomic gases are in which group?

Alkali meta

ls

Alkaline earth

...

Transition m

et...

Halogens

Noble gas

es

0% 0% 0%0%0%

1. Alkali metals2. Alkaline earth

metals3. Transition metals4. Halogens5. Noble gases

FAMILIES OF ELEMENTS Metals

◦Shiny ◦Solids◦Stretched and Shaped◦Conductors of heat and electricity

Nonmetals◦Solids, liquids or

gases◦Solids – dull and

brittle◦Poor conductors of

heat and electricity

****Semiconductors / Metalloids – exhibit properties of both metals and nonmetals

How do you tell if it’s a metal, nonmetal, or metalloid? Metals

◦ On the left hand side of the zigzag line (except for Hydrogen – exception)

- Metalloids or Semi-metals- Touching zigzag line (Except for Al)- Exhibit properties of both metals and nonmetals

Nonmetals◦ On the right hand

side of the zig zag line (plus Hydrogen)