General Chemistry 3

7/31/2019 General Chemistry 3

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Genaral Chem, Usama El-Ayaan





Experiments to determine what

an atom was

J. J. Thomson (1856-1940)

Noble prize 1906 in physics

- used Cathode ray tubes







( ) .

()




Voltage source

+-




Thomson’s Experiment

Voltage source

+-




Voltage source

+-




()


Voltage source

+-




Passing an electric current makes a beamappear to move from the negative to the

positive end


Voltage source

+-





positive end


Voltage source

+-





positive end


Voltage source

+-




Voltage source





Voltage source


By adding an electric field

+

-




Voltage source


+

-




Voltage source



+

-




Voltage source



+

-




Voltage source



+

-




Voltage source


.

+

-




() ( 1906

).







Found the electron Couldn’t find

positive (for a while)

Said the atom waslike plum pudding

A bunch of positive

stuff, with theelectrons able to be

removed




o

o




R. A. Millikan (1868-1953)Noble prize 1923 in physics

Three Nobel Laureates in Physics standing in front of the Athenaeum at California Institute of Technology (Caltech), 1931.

Front row from left: Albert A. Michelson, Albert Einstein and Robert A. Millikan.




-

+






Millikan’s Experiment

X-rays

.





-





They put an electric charge on the plates

--

++





--

++





-

+ + + + + + +

- - - - - - -





Measure the drop and find volume from 4/3πr3

Find mass from M = D x V

++

--





() .

++

--






http://localhost/var/www/apps/conversion/current/tmp/scratch1410/YouTube%20-%20Millikan%20Oil%20Drop%20Experiment.flv

http://localhost/var/www/apps/conversion/current/tmp/scratch1410/YouTube%20-%20Millikan%20Oil%20Drop%20Experiment.flv



Radioactivity

Discovered by accidentBequerel

Three types – alpha- helium nucleus (+2 charge, large

mass)

– beta- high speed electron

– gamma- high energy light




, β ,γ




E. Rutherford (1871-1937)Noble prize 1908 in chemistry




Rutherford’s Experiment

Used uranium to produce alpha particles Aimed alpha particles at gold foil by

drilling hole in lead block

Since the mass is evenly distributed ingold atoms alpha particles should go

straight through.

Used gold foil because it could be madeatoms thin




Lead

block

Uranium

Gold Foil

Florescent

Screen




What he expected




Because




Because, he thought the mass was evenly distributed in the atom




What he got




How he explained it

+

Atom is mostly empty

Small dense, positive piece at center

Alpha particles are deflected by it if they get close enough

:.1

.2( ).

.3() .




+




The atom is mostly empty space

Two regions

Nucleus- protons and neutrons

Electron cloud- region where you have a

chance of finding an electron

.()=

()..

.Genaral Chem, Usama El-Ayaan



Chadwick (1932)

4Be9 + 2He4 = 0n1 + 6C12

(1.6749x10

-24

gm)

=1840




(

( ))




Symbols

XA

Z

Na23

11




11H0

21H1

31H2

H D T




Å=10-10 m







Other terms

wave number: (cm-1.)

:

c

=3x108 ms-1

1




1 Å = 10-10 m = 10-8 cm = 10-4 m = 10-1 nm




c = in a vacuum is 3 x 108

m/s c =

What is the wavelength of light with a

frequency 5.89 x 105

Hz? 5.89 x 105 Hz

What is the frequency of blue light with a

wavelength of 484 nm? nm484




Nobel Prize in Physics in 1922


http://en.wikipedia.org/wiki/Nobel_Prize_in_Physics






410 nm

434 nm

486 nm

656 nm

Spectrum Genaral Chem, Usama El-Ayaan





The Bohr Ring Atom

n = 3

n = 4

n = 2

n = 1







( )

n > 1 1 (UV)

( )

n > 2 2 (Vis)

( )

n > 3 3 (IR)

( )

n > 4 4 (IR)

( )

n > 5 5 (IR)

(n1 = 1n2 = 2)

(n1 = 2n2 = 5)

(n1 = 4n2 = 6)




h is Planck’s constant h = 6.626 x 10-34 J s

N o b e l P r i z e i n P h y s i c

s i n 1 9 1 8 .

E = h

Said electromagnetic radiation is quantized in particles called photonsEach photon has energy = h = hc/

Combine this with E = mc2

you get the apparent mass of a photon

m = h / ( c)

Einstein

”“. h

Einstein Nobel Prize in Physics in 1921.Genaral Chem, Usama El-Ayaan




















http://www.lon-capa.org/~mmp/kap28/PhotoEffect/photo.htm





http://www.lon-capa.org/~mmp/kap28/PhotoEffect/photo.htm




E = mc2

E = mc2 = h = hc/

m = h / ( c)




de Broglie

.

= h/mv N o b e l P r i z e i n

P h y s i c s i n 1 9 2 9
























de Broglie




2pr = n















Nobel Prize in Physics in 1933Genaral Chem, Usama El-Ayaan















S orbitals




P orbitals




P Orbitals


D orbitals



D orbitals




F orbitals




F orbitals






sms

(½)+(½-)

Spin Quantum number











I n c r e

a s i n g e

n e r

g y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p6p

3d

4d

5d

7p

6d

4f

5f 6f

Orbitals available

to a Hydrogen atom


7



I n c r e

a s i n g e

n e r

g y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

With more electrons,

repulsion changes the

energy of the orbitals.




7



I n c r e

a s i n g e

n e r

g y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f


Fill from the bottom up following



Fill from the bottom up following

the arrows

1s2s 2p

3s 3p 3d

4s 4p 4d 4f

5s 5p 5d 5f

6s 6p 6d 6f

7s 7p 7d 7f

1s2

2 electrons

2s2

4

2p6 3s2

12

3p6 4s2

20

3d10 4p6

5s2

38

4d10 5p6 6s2

56





3d



4s

3p

3s

2p

2s

1s

1 H


3d



4s

3p

3s

2p

2s

1s

2 He


3d



4s

3p

3s

2p

2s

1s

3 Li


3d



4s

3p

3s

2p

2s

1s

6 C




3d



4s

3p

3s

2p

2s

1s

15 P


3d



4s

3p

3s

2p

2s

1s

26 Fe




[2He], [10Ne], [18Ar], [36Kr], [54Xe]

19 K : 1s2, 2s2, 2p6, 3s2, 3p6, 4s1

[Ar], 4s1

38 Sr : [Kr], 4s2





( :19K, 29Cu2+, Fe2+) (27Co)( ....... ) (28Ni2+)( ....... ) (1s2, 2s2, 2p6)

13 Al+, 12Mg3+, 9F-, 11Na-

(1s2, 2s2, 2p6)

13 Al3+,

12Mg2+,

9F+,

11Na+

(3s, 4p, 3f, 5d, 2d) (6s, 4p, 3d, 4f, 4s, 4d) ()

(2s2p, 2p2s, 3d4s, 2s5d, 4f 5p, ………………….)

(2s2p, 2p2s, 3d4s, 2s5d, 4f 5p, ………………….) (X2+) (3p6)

(X) (16, 18, 20, 22, 36)

( l

=

2)

(20

Ca) ..................



(m=-1) (20Ca)..................

(26

Fe)( .... ) (m=-2) (4d, 4f, 4p, 5d) (m=1)(s, p, d, f ) (n=3, l =2, m=1)(10, 6, 3, 2) (n=3, l =2)(10, 6, 3, 2)

( ) ((n, m), (n, l ), (n, s), (m, l ), (m, s), ( l , s))

((n, m), (n, l ), (n, s), (m, l ), (m, s), ( l , s)) (n=4, l =1) (17C l , 29Cu, 26Fe, 46Pd) ( l ) (n=4)(3, 4, 16, 32) (m) (n=4, l=3)(5, 7, 16, 32) (22, 23, 24, 30)(65Zn2+)

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General Chemistry 3