ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this...

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Page 1: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 2: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

ATOMIC THEORY

In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms.

He asked this question: If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further?

Democritus thought that it ended at some point, a smallest possible bit of matter. He called these basic matter particles, atoms.

Page 3: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Democritus (460-370

BC)• Proposed that matter is made of

tiny particles and empty space• atoms = smallest part of matter• different types of atom for each

type of matter

Page 4: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

People considered Aristotle's opinions very important and if Aristotle thought the atomic idea had no merit, then most other people thought the same also.

For more than 2000 years nobody did anything to continue the explorations that the Greeks had started into the nature of matter.

Page 5: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Lavoisier (1743-1794)

• Made measurements of a chemical change in a sealed container

• law of conservation of matter

Page 6: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Proust (1799)

• Observed that water is 11% H and 89% O.

• Law of definite proportionsdefinitions

Photo not

available.

Page 7: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• The principle that the elements that comprise a compound are always in a certain proportion by mass.

Page 8: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

In the 1800's an English chemist, John Dalton performed experiments with various chemicals that showed that matter, indeed, seem to consist of elementary lumpy particles (atoms).

http://antoine.fsu.umd.edu/chem/senese/101/atoms/dalton.shtml

Page 9: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Postulates

1. All matter consists of tiny particles.

2.Atoms are indestructible and unchangeable.

3.Elements are characterized by the mass of their atoms.

4.When elements react, their atoms combine in simple, whole-number ratios.

Page 10: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 11: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

J. J. Thomson(1897)

• Discovered the electron and proton

• Vacuum Tube Experiment

Page 12: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• The beam starts at the cathode.

• Cathode ray tube.• CRT

cathode -

anode +power source

Page 13: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• The beam is bent away from a negatively charged plate.

• Like charges repel.• The beam must be negative particles.

cathode -

anode +power source

Page 14: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• Positive particles were deflected from the anode.

cathode -

anode +power source

Page 15: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

THOMSON’S MODEL

In 1897, the English physicist J.J. Thomson discovered the electron and proposed a model for the structure of the atom. Thomson knew that electrons had a negative charge and thought that matter must have a positive charge. His model looked like raisins stuck on the surface of a lump of pudding.

Page 16: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

The Gold Foil Experiment

Page 17: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

“You, lab tech, just stay here and count the flashes of light. I’m going out to have a drink with the other professors” - Rutherford to Geiger

Page 18: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

“I say! It was like firing a gun at a tissue and having the bullet bounce

back at you!

Page 19: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

“You’re wrong. Do you hear me? You’re wrong! I say!” -Rutherford to Thomson

Page 20: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Experiment Conclusion

• The atom is mostly empty space.

• The atom contains a small, dense positive core.– Nucleus– If the nucleus was the size of a

golf ball the nearest electron would be one mile away.

– model

Page 21: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

RUTHERFORD’S MODEL

Rutherford knew that atoms consist of a compact positively charged nucleus, around which circulate negative electrons at a relatively large distance. The nucleus occupies less than one thousand million millionth of the atomic volume, but contains almost all of the atom's mass. If an atom had the size of the earth, the nucleus would have the size of a football stadium.

Page 22: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

•The small, dense, positively charged central core of an atom.

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same mass

smallest

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Particle Symbol Charge Mass (u) Mass (g)

Proton P+ +1 1 1.67x10-24

Neutron n0 0 1 1.67x10-24

Electron e- -1 .00055 9.11x10-28

Comparing Subatomic Particles

Page 25: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Atomic Number• Equals the

number of protons

• defines the element– all chlorine

atoms have 17 protons

17

ClChlorine

35.45

Page 26: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Mass number• Protons + neutrons• Isotope have

different masses– because they have

a different # of neutrons

• Chart mass is an average of the isotopes

17

ClChlorine

35.45

Page 27: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Mass number• What is the unit

for mass?• Atomic mass unit • symbol = u• based on carbon-

12• 1p+= 1n0 = 1u

17

ClChlorine

35.45

Page 28: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Why aren’t the electrons attracted to the nucleus?

Page 29: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

BOHR’S MODEL

In 1912 a Danish physicist, Niels Bohr came up with a theory that said the electrons do not spiral into the nucleus and with some rules for what does happen.

RULE 1: Electrons can orbit only at certain allowed distances from the nucleus.

RULE 2: Atoms radiate energy when an electron jumps from a higher-energy orbit to a lower-energy orbit. Also, an atom absorbs energy when an electron gets boosted from a low-energy orbit to a high-energy orbit.

Page 30: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

BOHR-SOMMERFIELD’S MODEL

According to the Bohr-Sommerfeld model, not only do electrons travel in certain orbits but the orbits have different shapes and the orbits could tilt in the presence of a magnetic field. Orbits can appear circular or elliptical, and they can even swing back and forth through the nucleus in a straight line.

Page 31: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

QUANTUM MECHANICAL MODEL

The visual concept of the atom now appeared as an electron "cloud" which surrounds a nucleus. The cloud consists of a probability distribution map which determines the most probable location of an electron.

Page 32: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

ATOM

ELECTRON CLOUD NUCLEUS

ELECTRONSPROTONS NEUTRONS

NEGATIVE POSITIVE NEUTRAL

1/1900 1

ATOMIC NUMBER (Z) ATOMIC MASS (A)

divisions

particlesparticles

chargecharge

Relative mass Relative mass

is

is

If atom is neutral

Page 33: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

N. Bohr(1885-1962)

• Proposed that the electrons orbited the nucleus .

• The further away the more energy was needed.

• Electrons only occupy orbits of certain energy.

Page 34: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

•Carry energy not matter

•Wavelength is the distance between corresponding points on the wave.

•Wavelengths per second = frequency

•1 wavelength/second = 1 Hertz (Hz)

Page 35: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

The Modern Model• Visible light

can be split into colored light.

• Each color has its own – frequency– wavelength– energy

• Red light has– low frequency– long wavelength– less energy

• Blue light has– high frequency– short wavelength– more energy

Page 36: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 37: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Gamma Rays….....Pass through most substances.

X rays…....Pass through soft tissue, but not bone.

UV light…….....causes sunburn, stopped by ozone

Light……………………………………………………..visible

Infrared………………………………………..radiant heat

Radiowaves…..Carry the sounds of radio stations.

Page 38: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

The Electromagnetic Spectrum

Page 39: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Electrons & Light

• When energy is put into an atom, electrons absorb the energy and become “excited”.

• Electrons can absorb only fixed amounts of energy.

• When excited, electrons move into a higher energy level (state).

Page 40: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Electrons & Light

• The electrons return to their original ground state.

• The electrons must give off energy in the form of light.

• This light has a specific frequency (and color.)

• This frequency shows up as a line when seen through a prism.

Page 41: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Flame Test

Page 42: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

The Modern ModelBright Line Spectra

When atoms absorb energy, from fire or electricity, the electrons give off light.•When viewed

through a prism a bright line spectra appears.•This is unique for every element.

H

HgNe

Page 43: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

The big gaps between spectral lines represent electron

transitions from one energy level to another.

hydrogen

Page 44: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

The groups of fine lines indicate that electrons are jumping from energy levels that are close in energy.

helium

Page 45: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

1

2

3

4

5

76

EN

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INFR

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Page 46: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Quantum Theory Model(Electron Cloud Model)

• Heisenberg Uncertainty Principle– You can never know

exactly where an electron is if you know how fast it is moving.

– If you know its exact location, you can’t know how fast it’s moving.

Page 47: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 48: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 49: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 50: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 51: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Electron Cloud Model

• Electron paths are not neat orbits.

• The region around a nucleus where an electron may be found is the electron cloud or orbital.

• An electron cloud is associated with a certain energy level.

Page 52: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

In 1927 Heisenberg formulated an idea which agreed with test results, that no experiment can measure the position and momentum of a quantum particle simultaneously. Scientists call this the "Heisenberg uncertainty principle." This implies that as one measures the certainty of the position of a particle, the uncertainty in the momentum gets correspondingly larger. Or, with an accurate momentum measurement, the knowledge about the particle's position gets correspondingly less.

Page 53: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Uncertainty Principle The position of a particle as well as its attributes cannot be determined with absolute precision. In association with this fact, a particle may disappear from one place and reappear elsewhere acausally.

The velocity (causal indeterminism) is coupled with uncertainty of position (acausal indeterminism). These indeterminate factors are added to the deterministic velocity to obtain the motion of the electron as the changing

position of its "locus of activity."

Page 54: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• The visual concept of the atom now appeared as an electron "cloud" which surrounds a nucleus. The cloud consists of a probability distribution map which determines the most probable location of an electron. For example, if one could take a snap-shot of the location of the electron at different times and then superimpose all of the shots into one photo.

• Note: Just as no map can equal a territory, no concept of an atom can possibly equal its nature. These models of the atom simply served as a way of thinking about them, albeit they contained limitations (all models do).

Page 55: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

What should a Model look like?

Scientific models may not always look like the actual object. A model is an attempt to use familiar ideas

to describe unfamiliar things in a

visual way.This is a painting of a young This is a painting of a young

woman by Pablo Picasso. Does woman by Pablo Picasso. Does it actually look like a young it actually look like a young

woman?woman?

Page 56: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Is this really an Atom?

The model above represents the most modern version of the atom.

(Artist drawing)

Many of the models that you Many of the models that you have seen may look like the one have seen may look like the one

below. It shows the parts and below. It shows the parts and structure of the atom. Even structure of the atom. Even

though we do not know what an though we do not know what an atom looks like, scientific atom looks like, scientific models must be based on models must be based on

evidence. evidence.

Page 57: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Atomic Models

ThomsonDalton

Rutherford

Bohr- Heisenberg

Page 58: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 59: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Electron Cloud Model

• A certain amount of electrons can exist in each energy level–1st level = 2–2nd level = 8–3rd level = 18

• Electrons in the outer most levels are valence electrons.

Page 60: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Sublevels & Orbitals

• Each energy level can be split into “sublevels”

• Each sublevel can be divided into “orbitals”.

Page 61: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Quantum Theory ModelOrbitals

One “s” orbital

Three “p” orbitals

Five “d” orbital

Page 62: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 63: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
http://chemsite.lsrhs.net/c_AtomicTheory/Images/orbitals.jpg
Page 64: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Tells the amount of energy

Tells the shape of orbital

Is a specific volume around the nucleus where two electrons

exist.

Page 65: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

1st energy level has 1 sublevel = 1s

2nd energy level has 2 sublevels = 2s, 2p

3rd energy level has 3 sublevels = 3s, 3p and 3d

4th energy level has 4 sublevels = 4s,4p, 4d and

4f

Page 66: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

s sublevel holds maximum 2 e-p sublevel holds maximum 6 e-d sublevel holds maximum 10 e-f sublevel holds maximum 14 e-

Page 67: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Placing electrons in orbitals:•orbital can hold a maximum of 2 e-•orbital has the same name as the sublevel•orbitals in the “s” sublevel are “s” orbitals

2s

yz

x

Page 68: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Placing electrons in orbitals:•orbital can hold a maximum of 2 e-•orbital has the same name as the sublevel•orbitals in the “p” sublevel are “p” orbitals

2px 2pz2py

Page 69: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

1, 2, 3, 4, 5, 6 or 7

s, p, d, or f (for the 4th energy level)

x, y, or z (for the p sublevel)

Page 70: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

SUBLEVEL ORBITALS ELECTRONS

s 1 2

p 3 6

d 5 10

f 7 14

Page 71: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 72: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 73: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 74: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

The most stable arrangement of electrons in sublevels and orbitals.

Page 75: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

For Aluminunum

1s 2s 2p 3s 3p1

Electron Configurations

sublevelsublevelnumber of number of

electrons in electrons in the sublevelthe sublevel

2

2

6

2

Page 76: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

For Manganese

1s 2s 2p 3s 3p 4s 3d 6

Electron Configurations

sublevelsublevelnumber of number of

electrons in electrons in the sublevelthe sublevel

2

2

6

2

2

5

Page 77: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
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Page 79: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

1s

2s 2p3s 3p4s 3d 4p5s 4d 5p6s

4f

5d 6p7s

5f

6d

Page 80: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Suble

vel Fi

lling

Ord

er

7s 7p 7d

6s 6p 6d 6f

5s 5p 5d 5f

4s 4p 4d 4f

3s 3p 3d

2s 2p

1s

Page 81: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Try these electron configurations!

10Ne =

11Na =

12Mg =

18Ar =

19K =

1s2 2s2 2p6

1s2 2s2 2p6 3s1

1s2 2s2 2p6 3s2

1s2 2s2 2p6 3s2 3p6

1s2 2s2 2p6 3s2 3p6 4s1

Page 82: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Déjà vu!

10Ne =

11Na =

12Mg =

18Ar =

19K =

1s2 2s2 2p6

1s2 2s2 2p6 3s1

1s2 2s2 2p6 3s2

1s2 2s2 2p6 3s2 3p6

1s2 2s2 2p6 3s2 3p6 4s1

Look! It’s Look! It’s neon!neon!

Ar?!Ar?!

Page 83: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Let’s make this shorter.

10Ne =

11Na =

12Mg =

18Ar =

19K =

1s2 2s2 2p6

1s2 2s2 2p6 3s1

1s2 2s2 2p6 3s2

1s2 2s2 2p6 3s2 3p6

1s2 2s2 2p6 3s2 3p6 4s1

[Ne]

[Ne]

[Ar]

Page 84: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Noble Gas Notation

10Ne =

11Na =

12Mg =

18Ar =

19K =

1s2 2s2 2p6

[Ne] 3s1

[Ne] 3s2

1s2 2s2 2p6 3s2 3p6

[Ar] 4s1

Page 85: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Last Filled Sublevel for Noble Gases

1s2

2p6

3p6

4p6

5p6

6p6

Page 86: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

Try these electron configurations!

26Fe =

47Ag =

79Au =

20Ca =

40Zr =

[Ar] 4s2 3d6

[Kr] 5s2 4d9

[Xe] 6s2 4f14 5d9

[Ar] 4s2

[Kr] 5s2 4d2

Page 87: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
Page 88: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,
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Page 91: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• SUMMARY • 1. De Broglie first pointed out the wave-particle duality

of nature. His ideawas that all particles exhibit some wave characteristics, and vice versa.

• 2. The momentum of an object is the product of its mass and velocity. Wavelength varies inversely as momentum.

• 3. Heisenberg's uncertainty principle concerns the process of observing an electron's position or its velocity. It is impossible to know accurately both the position and the momentum of an electron at the same time.

• 4. Schrodinger developed a mathematical equation which describes the behavior of the electron as a wave. The solution set of the wave equation can be used to calculate the probability of finding an electron at a particular point.

Page 92: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• 5. Because of the electron's high velocity, it effectively occupies all volume defined by the path through which it moves. This volume called the electron cloud.

• 6. The principal quantum number (n = 1, 2, 3,..) is the number of energy level and describes the relative electron cloud size.

• 7. Each energy level has as many sublevels as the principal quantum number. The second quantum number (1 = s, p, d, f...) describes the of the cloud.

Page 93: ATOMIC THEORY In 460 B.C., a Greek philosopher, Democritus, develop the idea of atoms. He asked this question: If you break a piece of matter in half,

• 8. The third quantum number, m, describes the orientation in space of orbital. 9:10, 9

• 9. The fourth quantum number, s, describes the spin direction of an electron.

• 10. Each orbital may contain a maximum of one pair of electrons. Electrons in the same orbital have opposite spins. s:12

• 11. Pauli's exclusion principle states that no two electrons in an atom have the same set of quantum numbers.

• 12. Electrons occupy first the empty orbital giving the atom the lowest energy.

• 13. The diagonal rule can be used to provide the correct electron configuration for most atoms.

• 14. The chemist is primarily concerned with the electrons in the outer energy level. Electron dot diagrams are useful in representing the outer level electrons.


Democritus This is the Greek philosopher Democritus who began the search for a description of matter more than 2400 years ago. This is the Greek philosopher.

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The Development of Atomic Models Democritus was a pre- Socratic Greek philosopher (born around 460 BC). Democritus was originator of the belief that all.

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Atomic Theory - Davis School · PDF fileThe First Atomic Hypothesis •Democritus (460 – 370 BC): –Greek philosopher –Speculated that matter is composed of atoms which move through

Atomic Theory - Davis School · PDF fileThe First Atomic Hypothesis •Democritus (460 – 370 BC): –Greek philosopher –Speculated that matter is composed of atoms which move through

Atoms, Molecules, and Ions Defining the Atom The Greek philosopher Democritus (460 B.C. – 370 B.C.) was among the first to suggest the existence of atoms.

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Originally)created)by)D.)Enns,)United)Nations ...ss.cms.rockwallisd.org/UserFiles/Servers/Server_125926/File/Babb... · But First, Democritus! Democritus was a Greek philosopher (470-380

Originally)created)by)D.)Enns,)United)Nations ...ss.cms.rockwallisd.org/UserFiles/Servers/Server_125926/File/Babb... · But First, Democritus! Democritus was a Greek philosopher (470-380

EARLY ATOMIC THEORIES. DEMOCRITUS The Greek philosopher Democritus (460-370BC) was the first person to propose the idea that matter was not infinitely.

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Democritus -Greek philosopher 450 BC. Aristotle -born 384 BC -Greek philosopher, educator & scientist -student of plato.

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Atomic Theory. Democritus The Greek philosopher Democritus (460 B.C. – 370 B.C.) was among the first to suggest the existence of atoms (from the Greek.

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Chapter 7 Atomic Structure and Periodicity. Democritus 400 BC Greek philosopher Suggested atoms Used intuition.

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ATOMIC STRUCTURE ? Kenneth E. Schnobrich. A Brief History About 460 B.C. - a Greek Philosopher, Democritus, developed the idea of atoms (atomos) as small.

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Atomic Theory Date. Democritus Date 460-370 B.C. Democritus was a philosopher; did no research He thought that everything was made up of tiny round things.

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1 Quantum Mechanics Chapters 4 & 5. 2 WAY WAY BACK IN TIME... Greek philosopher Democritus (460- 370 BCE.) Greek philosopher Democritus (460- 370 BCE.)

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Democritus (460-370 B.C.)

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The History of Atomic Theory Mr Nelson. Democritus The Greek philosopher Democritus began the search for a description of matter more than 2400 years.

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