Atomic structure

Atomic Structure There are three subatomic particles which

make up atoms 1) Protons: 1 AMU, Positive charge 2) Neutrons: 1 AMU, Neutral charge 3) Electrons: (virtually) 0 mass, negative ChargeAtomic Mass Unit (AMU): 1/12

th the mass of a single carbon

atom… actually equal to: 1.660 538 782(83) × 10−24… This is a unit used to measure the mass of a single proton or neutron

YES: Quarks are fundamental matter particles that are constituents of neutrons and protons and other hadrons (Hadrons are particles made from quarks and/or

gluons- carrier particle of the bond). There are six different types of quarks. Each quark type is called a flavor

(up, down, charm,strange, top, bottom).

Oh…thaaaat’s a quark

What is this? This is a model of a plot of the probability of where electrons would be found in a hydrogen atom: Based on the Bohr experiments

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

1) All matter is made of atoms. Atoms are indivisible and indestructible. (True/False)

2) All atoms of a given element are identical in mass and properties (True/False)

3) Compounds are formed by a combination of two or more different kinds of atoms. (True/False)

4) A chemical reaction is a rearrangement of atoms. (True/False)

e- e-Hey Baby…you get

me spinning…where you live?

I live at 1s2, 2s2, 2p5

Pick me up at 6:30

Where is that? Maybe you should draw me a map

Quantum numbersN: Shells- average distance from the nucleus as well as its energy: 1,2,3,4,5,6,7,8… more energy will mean less stabilityL: Subshells- angular momentum, which describes the shape of the electrons orbital: 0, 1,2…Ml: Orbitals- magnetic quantum number or orbital describes the orientation of the orbital in space (ie: x,y,z axis)Ms: positive or negative spin direction when paired up in the same orbital

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This is how far the electron is from the nucleus. 1st energy level: 2 electrons2nd energy level: 8 electrons3rd energy level: 18 electrons4th energy level: 32 electrons5th energy level: 32 electronsEtc…

I wonder how many electrons go into each energy level

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L: Subshells Subshells are the shapes of the orbits that electrons take

around the nucleus of an electron: S, P, D, F, (G, H) 1st shell (N=1): 1 subshell, s (l = 0) 2nd shell (=2): 2 subshells s (l = 0), P (l =1) 3rd shell (N=3): 3 subshells, s (l = 0), p (l =1), d (l = 2) 4th Shell (N=4): 4 subshells, s (l = 0), p (l =1), d (l = 2), f (I =3) 5th Shell (N=5): 5 subshells, s (l = 0), p (l =1), d (l = 2), f (I =3), g (I = 4)

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Orbitals

Subshell shapesS (l = 0)-sphere (1 per energy level)

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P (l = 1) subshell (3 per energy level they are found in) AP

D (l = 2) subshell (5 per energy level they are found in) 5 orientations

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F (l = 3) subshell (7 per energy level they are found in)7 orientations

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There is also G, H, IThese are so convoluted that there is no real

defined shape… only that they exist

How does the l relate to Ml? It is all about orientation

Orbitals: MlThe spatial orientation… sort of X,Y, Z axisS subshell: (l = 0), has one orbital, Ml = 0P subshell (l = 1), has 3 orbials, Ml = -1, 0, or +1D subshell (l = 2), has 5 orbitals, Ml = -2, -1, 0, +1, or +2F subshell (l = 3), has 5 orbitals, Ml =-3, -2, -1, 0, +1, +2, or + 3

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Holy Guacamole…That’s pretty complicated!! No worries. Just remember that each orbital

of each subshell at each energy level can hold no more than 2 electrons

The total S orbitals for each energy level (1) X 2 = 2 The total P orbitals for each energy level (3) X 2 = 6 The total D orbitals for each energy level (5) X 2 = 10 The total F orbitals for each energy level (7) X 2 = 14

That’s really all that matters when it comes to orbitals

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Ms Spin directionWhen electrons share the same orbital with

in their subshells, they pair up because the electrons start spinning opposite directions… To signify this we indicate it as + ½, and – 1/2

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Putting it togetherQuantum numbersWrite the quantum numbers for the atom of

the following:Na: (3,0,0, ½)

Rb: ( 5, 0, 0, ½)

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Now What???

So now I know what energy levels are and what orbitals are aaand how many electrons I can put in each. What is my next move???

Follow the Map The diagonal chart

Electrons fill in

ORDER from lowest

to highest energy

level… mostly

Think you need a GPS for this address?

Here’s an easy way:The diagonal Chart1s

2s

3s 2p

4s 3p

5s 4p 3d

6s 5p 4d

7s 6p 5d 4f

8s 7p 6d 5f

Remember:Each s orbital is 1 x 2 = 2 e-Each p orbital is 3 x 2 = 6 e-Each d orbital is 5 x 2 = 10 e-Each f orbital is 7 x 2 = 14 e-

All electrons will fill in this order at GROUND STATE: The state of least possible energy in a physical system, as of elementary particles. Also called ground level

What time is it?

Time to Hammer it home H: 1s1

N: 1s2,2s2, 2p4

Ne: 1s2,2s2, 2p6

s block d block p blockf block

Hunds Rule When an electron is added to a subshell it will always

occupy an empty orbital if there is one available (why doesn’t this apply to S orbitals?)

Diamagnetic: all electrons paired up in all orbitals Paramagnetic: 1 or more electrons not paired in any

orbitals

AP

What are the Ground State Electron Configurations of the following:

Mg:Ca:C:He:Ar:

What observations can you make about Mg and Ca?

Mg:1s2, 2s2, 2p6, 3s2

How many Valence shell e- ? 2

Ca: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2


C:1s2, 2s2, 2p2 How many Valence shell e- ? 4

What observations can you make about He and Ar?

He: 1s2


Ar: 1s2, 2s2, 2p6, 3s2, 3p6


What observations can you make about Mg and Ca?

Mg:1s2, 2s2, 2p6, 3s2


Ca: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2


C:1s2, 2s2, 2p2 How many Valence shell e- ? 4

What observations can you make about He and Ar?

He: 1s2


Ar: 1s2, 2s2, 2p6, 3s2, 3p6


AnswerAnswer

Orbital DiagramsA way to represent each electron of an

atom/ion numerically and visually.

Also used to determine if an atom/ion is paramagnetic or diamagnetic

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ExampleAP

Procedure:Always fill one electron in each orbital and

one in each orientation (Ml) before pairing with in the same orbital

Always fill from lowest energy level on up- if electrons are higher than that then the atom is in an excited state

If all electrons are paired in all orbitals, then it is Diamagnetic, if one electron is unpaired in an orbit, than it is paramagnetic

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Example: which is the right way to write the orbital diagram for the electron configuration: 1S2, 2S2, 2 P4? And is this Diamagnetic or paramagnetic?

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AnswerB

and it is paramagnetic

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The Aufbau principleIn electron configurations the electrons are

placed in order of increasing energy

The Pauli exclusion principleWith in an atom, no two electrons can have

the same set of quantum numbers

Electrons and EnergyAs electrons are farther from the nucleus,

their potential energy increases in the same way that yours would as you climbed a ladder

Electron energy is Quantized, meaning that the energy of the electron is related to the specific energy level it is at and the energy required to keep it there…. So the higher the energy level, the higher the energy.

The electrons do not exist between energy level but at very discrete levels (N)

AP

Calculating the energy of an electron

En = -2.178 X10-18 Joules

En = the energy of the electronN = principle quantum number of the

electron

N2

AP… just know

setup… no

calculation

Energy and Electromagnetic radiation

E = hc

Where :E = Energy releasedH = Planck’s constant: 6.63 x 10-34

c = constant speed of light: 3.00 x 108 m/s= wavelength

AP… just know

setup… no

calculation

We concentrate mostly on certain electrons called Valence electrons: THE VALENCE SHELL ELECTRONS: These are the electrons found in the outer most

shell of the atom: the S and the P orbitals of the outer most energy level

Valence shell electrons are determined by the roman numeral above the groups on the periodic table

These determine the atomic radii

Atomic Radius: Distance from the nucleus to the edge of the

valence shell cloud usually in Angstroms or picometers; all based on probability since electrons are always moving

Relative Atomic Radii



Electronegativity The ability to take and hold electrons to itself-

electrostatic (magnetic) attraction (opposites attract)

Relative Electronegativity



Compare Electronegativity to atomic radius IN general as atomic radius increases

electronegativity…

Answer DECREASES

Atomic Radius and Electronegativity

Use the periodic table to determine the following.

N or Cs Which has the highest electronegativity? Which has the largest radius?

Answer Highest Electronegativity: N

Largest Radius: Cs

Ionization energyThe energy required to remove an electron from an

atom is called the first ionization energy … Energy required to remove the second electron from an atom is called the second ionization energy (requires more energy than 1st)… so on

Energy is required because the electron is attracted to the nucleus electrostatically

Ionization energy tends to increase going left to right, however there is a shielding effect an also as e- pair up in the same P orbital, it decreases slightly

IE decreases going down the PT in the same group because of distance and electron shielding effect

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Ionization energy sequenceEach time that you remove an electron from an

atom there is more required energy, so the more e- removed the more the IE increases… Once the final electron is removed which eliminates the last valence electron there will be a large jump in energy because the ion is now stable… example: Si

780kJ, 1575 kJ, 3220 kJ, 4350 kJ, 16100 kJ

Notice that there are 4 IEs and the last one is very large compared to the others

IE periodic tableAP

Electron affinityA measure of the change in energy of an

atom when an electron is added to itIf the addition makes it more stable, then

energy is given offOn rare occasions (alkaline earth metals and

Nobel gases) the addition of an e- makes the atom less stable and therefore requires energy

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EA periodic tableAP

EN, EA, IEWhat are the periodic trends when

comparing these 3 electron characters?

They are similar

Weird!!!!!

AP

A historical perspective of atomic structure

ReviewJohn Dalton: Atomic theory, named elements,

conservation of massDmitre Mendeleev (Lothar Meyer)- arranged

elements into periodic table

J.J. ThomsonNoted deflections of the cathode ray

and determined that atoms were both positive and negative

The Plum pudding model: JJ Thomson

Robert MillikanExamined the behavior of charged oil drops

in an electric field

Calculated the charge on an electron

Ernest RutherfordNoticed how alpha particles scattered when passed through gold foil

4 He2+

From this he determined that the center of the atom (nucleus) must be the area that has the positive and that the atom was mostly empty space

2

Quantum TheoryMax Planck: EM energy is quantized based

on a unit called a quantum or photon (E = hv) So EM energy does not change smoothly but in distinct steps

This would make a photon a UNIT of energy or a particle, yet it has wave properties

The Bohr model

Werner HeisenbergHeisenberg uncertainty principleStated that it is impossible to know both the

position (particle) and the momentum (wave) of an electron at a particular instant

Can only calculate the probability of electron positions

The de Broglie (Pr: De Broy) hypothesisSaid that all matter has wave characteristics

and there is a mathematic relationship between electron waves and particles

h

is wavelength, h is plancks constant, mv (mass x velocity) momentum of the particle

mv

Atomic structure

Technology

energy level ap

electrons orbital

p subshell

orbitals ap

total s orbitals

highest energy level

d subshell

orbital ap