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Chemistry
Chemistry
Chemistry is the study of the composition, properties, and
transformations of matter.
2N CO2 +
2 N H2O + PHOTONS
→ 2(CH2O)N + 2N O2
CARBON DIOXIDE + WATE R + LIGHT ENERGY → CARBOHYDRATE + OXYGEN
C6H12O6 + 6O2 → 6H 2O +6CO2+energy
KIM 101E General Chemistry
Mustafa Özcan
http://www.kimya.itu.edu.tr
Text Book :
Genelral Chemistry, R. H. Petrucci, W.S. Harwood, Prentice Hall
International, Inc., 2002, 8th Ed.
Chemistry a molecular approach Nivaldo J Tro Pearson Education
2008
and
all other chemistry books
1st Midterm : 7 Nov. 2009 Saturday 10-12 (Topic: 1,2,3,4,5,6,7,9,10)
2nd Midterm : 19 Dec. 2009 Saturday 10-12 (Topic: 11,12,13,14 )
Final : All topics
Grading:
1st Midterm 25%, 2nd Midterm %25, and Final 50 %
WEEK
DATE
TOPICS
1
1 Oct. 2009
Electronic Structure of Atom (Chp:1-2-9)
2
/08 Oct. 2009
Periodic Table, Chemical Compounds (Chp:10 ve 3)
3
15 Oct. 2009
Chemical Reactions, Reactions in Aqueous Solutions (Chp:4 ve 5)
4
22 Oct. 2009
Gases (Chp:6)
5
29 Oct. 2009
6
05 Nov. 2009
Thermochemistry (Chp:7)
7 Nov. 2009
1st Midterm (Topic: 1,2,3,4,5,6,7,9,10)
7
12 Nov2009
Chemical Bonding –I (Chp:11)
8
19 Nov 2009
Chemical Bonding –II (Chp:12)
9
26 Nov 2009
10
03 Dec. 2009
Liquids, Solids, and Intermolecular Forces (Chp:13)
11
10 Dec. 2009
Liquids, Solids, and Intermolecular Forces (Chp:13)
12
17 Dec. 2009
Solutions and Their Physical Properties (Chp:14)
19 Dec. 2009
2nd Midterm (Topic: 11,12,13,14)
13
24 Dec. 2009
Chemical Equilibrium (Chp:16)
14
31 Dec. 2009
Acids and Bases (Chp:17)
MATTER
 is anything that occupies space and has mass
 All matter is formed from one or more of 114 presently
known elements—fundamental substances
Early Chemical Discoveries
 Antonie Lavosier:
 LAW OF MASS CONSERVATION Mass is neither created nor destroyed in chemical
reactions.
 French chemist Joseph Proust:
 LAW OF DEFINITE PROPORTIONS Different samples of a pure chemical substance
always contain the same proportion of elements by mass
 John Dalton (1766–1844), proposed a new theory of matter as follows:
 Elements are made of tiny particles called atoms.
 Each element is characterized by the mass of its atoms. Atoms of the same element
have the same mass, but atoms of different elements have different masses.
 Chemical combination of elements to make different substances occurs when atoms join
together in small whole-number ratios.
 Chemical reactions only rearrange the way that atoms are combined; the atoms themselves are
unchanged.
Subatomic particles.
 1897 J.J Thomson proposed that cathode rays must consist of tiny
negatively charged particles, which we now call electrons. Thomson was
able to calculate the ratio of the electron’s electric charge to its mass—its
charge-to-mass ratio, e/ m = 1.758 820 x 108 C/g
 Robert Millikan found mass of electron as 9.109 382 x 10-28 g by oil drop
experiment
 Ernest Rutherford found that atoms also contain positively charged
particles. in 1911
 Rutherford proposed that most of the mass and positive charges of an atom
are concentrated in a tiny central core that he called the nucleus.
 1932 James Chadwick discovered some subatomic particles other than
protons named neutrons.
Subatomic particles.
Particle
name
Symbol
Electric Charge
Coulomb C
Relative
Electric
Charge
Mass g
Atomic mass
unit
Location
Proton
p+
+1.602 x 10-19
+1
1.673x10-24
1.0073
Inside
nucleus
Neutron
n
0
0
1.675x10-24
1.0087
Inside
nucleus
Electron
e-
-1.602 x 10-19
-1
9.109x10-28
0.00055
Outside
nucleus
A
X
Z
Atomic number Z = Number of protons in atom’s nucleus= Number of electrons
around atom’s nucleus
A = Z + N.
Mass number (A) = Number of protons (Z) + Number of neutrons (N)
İsotopes : atom with the same number of protons but different numbers of
electrons are called isotope
1
H
1
2
H
1
3
H
1
Ion: an atom or group of atoms which either positevely charged or negatively charged
As a result of the loss or gain of electrons
 (p-e)
A
X
Z
Electrons in Atom
Lights has many characteristics in common with electrons
Light is a kind of electromagnetic wave carrying energy. ( Waves can
be identified as a motion carrying energy)
• The wave nature of light
• The particle nature of light
The wavelength () is the distance
between any two identical points in
consecutive cycles.
Unit
Symbol
(m)
Angstrom
Å
10-10
Nanometre
nm
10-9
Mikrometre
m
10-6
Millimetre
mm
10-3
sentimetre
cm
10-2
Metre
m
1
The frequency () is the number of wave
cycles that pass a point each second. Its
unit is 1/second (Hertz) .
The amplitude of a wave is its height
the velocity of a wave is the product
of its frequency and its wavelength,
for light
c = . 
Elektromagetic spectra
• question: calculate the frequency, in s-1, of an Xray that has a wavelength of 8.21nm
Particlelike Properties of Electromagnetic
Radiation:
• Quantum theory: (1900 The Planck Equation)
E= h. . = h c / 
h=Planck constant = 6.626 x 10-34 J.s
• Photoelectric effect : ( 1905 Albert Einstein)
When a beam of light shines on certain surfaces particularly certain metals, e beam of
electrons is produced. This phenomenon is called the photoelectric, Einstein
considered that electromagnetic radiation has particle like characteristics and that
particles of light called photons, posses a characteristic energy, given by planck’s
equation.
calculate the energy of X ray having 8,21nm vawelength
calculate the energy of the violet light that has 6,15x1014s-1 frequency
Arrange the followings in order to increasing vawelength
and energy per photon
a- X-Ray
b- UV
c- Visible light
d- Microwave
e- Infrared
• A nitrogen gas laser pulse with wavelength of 337nm contains
3.83mJ of energy. How many photons does it contain?
Bohr Atom Theory
En = - Rh / n2
Rh= 2.179 x 10 –18 J
En = - Rh / n2
Rh= 2.179 x 10 –18 J
ΔE = Ef – Ei =
1
–
= RH (
2
ni
-RH
nf
2
–
-RH
n i2
1
) = h = hc/λ
2
nf
• Calculate the energy change in electron transition from Hirojen
n=5 to n=3 in hydrogen atom
• Determine the wavelength of light emitted when an electron in a
hydrogen atom Hiydrogen atom makes a transition from an
orbital n=6 to n=5.
Bohr Atom Theory
• the electrons in an atom move at a certain distance from nucleus and
their motions are stable . Each stationery state has a definite energy.
• Electrons move in each stationary energy state in a circular orbital.
These circular orbitals are called energy levels or shells. The possible
states for the electron are numbered, n=1, 2, 3 and so on.
• When an electron is in a stationary state, the atom does not emit light.
However when an electron falls back to a lower energy level from a
higher one, it emits a quantum of light that is equal to the energy
differences between these two energy levels.
the Heisenberg Uncertainty Principle
•
•
imagine what would happen if we tried to determine the position of an electron at a
given moment. For us to “see” the electron, light photons of an appropriate
frequency would have to interact with and bounce off the electron. But such an
interaction would transfer energy from the photon to the electron, thereby
increasing the energy of the electron and making it move faster. Thus, the very act
of determining the electron’s position would make that position change. In
mathematical terms, Heisenberg’s principle states that the uncertainty in
the electron’s position, times the uncertainty in its momentum, is equal to or greater
than the quantity h/4p:
Δx Δp ≥
h
4π
h
= ------------m.

DE BROGLIE EQUATION
the mass of an electron is 9,109x10-28g and its velocity 5,97x106 m/s,
what is the wavelength of this electron?
Quantum Numbers
 The principal quantum number (n) is a positive integer on which the size and
energy level of the orbital primarily depend. n= 1, 2, 3,4, 5,6,7
 The angular-momentum quantum number (l) defines the three-dimensional
shape of the orbital. l can have any integral value from 0 to n-1
If n = 1, then l = 0 2
If n = 2, then l = 0 or 1
If n = 3, then l = 0, 1, or 2
 The magnetic quantum number (ml)defines the spatial orientation of the
orbital with respect to a standard set of coordinate axes. Ml can have any integral value
ml = from -l to + l .
 spin quantum number electrons behave as if they were spinning around an
axis,much as the earth spins daily. Unlike the earth, though, electrons are free to
spin in either a clockwise or a counterclockwise direction. This spinning charge
gives rise to a tiny magnetic field and to a spin quantum number (which can have
either of two values, -1/2 or +1/2)
s orbitals
l= 0
ml= 0
p orbitals
I =1
ml= -1,0,+1
d orbitals
l =2
ml =-2,-1,0,+1,+2
f orbitals
l =3
ml= -3,-2, 1,0,+1,+2,+3
_
___
_____
_______
s
p
d
f
max e: 2
max electron: 6
max electron:10
max electron: 14
Electron Configurations of Multielectron Atoms
.
- Lower-energy orbitals fill before higher-energy orbitals
1s -2s -2p -3s- 3p –4 s-3d -4p -5s -4d -5p –6s-4f –5d -6p -7s -5f 6d (Aufbau),
• no two electrons in an atom can have the same four quantum numbers. In
other words, the set of four quantum numbers associated with an electron
acts as a unique “address” for that electron in an atom, and no two electrons
can have the same address.(Pauili)
• HUND’S RULE If two or more orbitals with the same energy are
available, one electron goes in each until all are half-full. The electrons in
the half-filled orbitals all have the same value of their spin quantum
number.
Diamagetic: the state of an atom or ion that
contains only paired electrons
Paramagnetic: the state of an atom or ion that
contains only unpaired electrons
İsoelektronic: atoms or ions which have the
same numbers of electron are isoelectronic.
(same electron configuration)
Question: which one shows the quantum numbers of last electron of
Neutral Na atom has the elecron configuration as 1s2 2s2 2p6 3s1
a- n=1 l=0 ml=0 ms= +½
b- n=3 l=1 ml=0 ms= +½
c- n=3 l=0 ml=1 ms= +½
d- n=1 l=1 ml=1 ms= +½
e- n=3 l=0 ml=0 ms= +½
Soru: which one has the paramagnetic properties
a- 2He
b- 18Ar
c- 20Ca
d- 30Zn
e- 40Zr
explain the following quantum numbers are possible or
not?
a.
b.
c.
d.
n=3
n=3
n=2
n=5
l=2 ml=-1
l=3 ml=-3
l=3 ml=-1
l=2 ml=-1