General Chemistry 1 Module. Discussion on the different properties of Matter. Models of atom and history. Different orbitals and spdf notation. Identification of Atomic Mass, Weights, and Abundances of Isotopes.
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Research or teaching not for you?
Chemistry is so deeply ingrained into so many
areas of business, government, and
environmental management that some
background in the subject can be useful (and
able to give you a career edge as a team
member having special skills) in fields as varied
as product development, marketing,
management, computer science, technical
writing, and even law.
3. Chemistry in the Modern World
-the study of matter and the changes that material
substances undergo.
-extensively connected to other field of study.
Geologist – minerals and rocks identification through
chemical techniques
Oceanographer – use chemistry to track ocean currents and
nutrients of the sea
Engineers – structures and properties of substances
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4. 4
Physicists – properties of substance to detect
new subatomic particles
Astronomers – chemical signatures to
determine age and distance of stars
Biochemistry – application of chem to
biological processess
5. The Scientific Method
How scientists search for answers; be inquisitive (sometimes attitude).
Observation -> Hypothesis -> Experimentation -> Conclusion -> Model
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• Qualitative
• Quantitative
Observation
• Null (Ho)
• Alternative (Ha)
Hypothesis
• Procedures
• Methodological
Experiment
Chemists expand their knowledge by making observations,
carrying out experiments, and testing hypotheses to develop laws
to summarize their results and theories to explain them. In doing
so, they are using the scientific method.
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A Description of Matter
Chemists study the structures, physical
properties, and chemical properties of
material substances– anything that
occupies space and has mass.
The Mass of an object is the quantity of
matter it contains. Mass is different from
weight as it is dependent on its location
(gravitational force). Mass- lb, Weight- Kg
8. STATES OF MATTER
Solid – definite shape and volume
Liquid – definite volume
Gas – lacking defined volume and shape
Plasma – exist at very low temp, particles
carry an electrical charge
Other states of matter:
Bose Einstein Condensate
Superfluid
Fermionic condensate
Rydberg matter
Photonic matter
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PROPERTIES OF
MATTER
According to change involved
during measurement of the
property
According to dependence on
amount of matter
Physical Properties Chemical Properties
Extensive
Properties
Intensive
Properties
What is the difference between Chemical and Physical Properties?
Intensive and Extensive Properties?
10. ✘ Characteristics that can be measured w/o
changing the composition
✘ Amount of space occupied by a sample
✘ Mass, Color, Volume
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Physical Properties
Extensive
or
Intensive
Chemical Properties
✘ Ability of substance to react and form new
substance
✘ Flammability and Susceptibility to corrosion
✘ All pure substance have the same physical and
chemical property (ex. Pure copper is always reddish-
brown solid (Px) and always dissolves in dilute HNO3 to
produce a blue solution and a brown gas(Cx))
11. Extensive
(dependent on amount of substance)
39 g
18.8 cm3
Mass
Volume
0.84 g
4.1 cm3
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Intensive
(independent of amount of substance)
Yellow
115.2 C
Color
Melting Point
Yellow
115.2 C
Sulfur Crystal Sulfur Powder
Because they differ in size, the two samples of Sulfur have different
extensive properties, such as mass and volume. In contrast, their
intensive properties, including color, melting point, and electrical
conductivity, are identical
12. Though Mass and Volume are both extensive properties,
their ratio is an important intensive property called
Density (d).
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Density
✘ Mass per unit Volume
✘ Express in grams per cubic cm (g/cm3)
✘ Directly proportional to mass, inversely to volume
Lead with its greater mass, has a far greater density than the
same volume of air, just as a brick has a greater density than the
same volume of Styrofoam. At a given temperature and pressure, the
density of pure substance is a constant.
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Simple Application:
We can identify the weight of 1 hectare soil with only the
density of 1 cm3, suppose we have 1.33 g/cm3 density (g/cm3=t/m3)
Dimension of 1 ha = 10,000 m2 with a depth of 0.2 m
d=m/v
1.33 𝑡𝑜𝑛𝑠
𝑚3
=
𝑥
(10,000𝑚2)(0.2𝑚)
1.33 tons(2,000 m3)
𝑚3 =
xm3
𝑚3
X = 2,660 tons (2 million Kg soil)
14. For Example, pure water, has a density of 0.998 g/cm3 at
25 0C. (density of water changes with temperature,
inversely)
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density = mass / volume d = m/v
Substance Density at 25
0C (g/cm3)
Blood 1.035
Body fat 0.918
Whole milk 1.030
Corn oil 0.922
Mayonnaise 0.910
Honey 1.420
Densities of common substances
*Notice that corn oil has lower mass to
volume ratio than water. This means that
when added to water, corn oil will “float”.
15. Sample computations
Imagine you have five bottles containing colorless liquids (label A-E).
You must identify them by measuring the density of each. Using a
pipette, you carefully measures 25 mL of each liquid into 5 beakers
of known mass (1 mL = 1 cm3). You then weigh each sample on a lab
balance. Based solely on your results, can you ambiguously identify
all the five liquids?
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A B C D E
17.72 19.75 24.91 19.65 27.80
Grams:
16. d = m / v
A. 17.72 g/25 mL (cm3) = 0.7088 g/cm (cubed)
B. 19.76 g/25 cm3 = 0.7900 g/cm3
C. 24.91 g/25 cm3 = 0.9964 g/cm3
D. 19.65 g/25 cm3 = 0.7860 g/cm3
E. 27.80 g/25 cm3 = 1.122 g/cm3
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17. Distinctive physical and chemical properties of the
element sodium:
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Physical properties (25 °C) Chemical properties
•appearance: a soft, shiny metal
•density: 0.97 g/cm3
•melting point: 97.5 °C
•boiling point: 960 °C
• forms an oxide Na2O and a hydride NaH
• burns in air to form sodium peroxide
Na2O2
• reacts violently with water to release
hydrogen gas
• dissolves in liquid ammonia to form a
deep blue solution
18. The Basics of
Chemistry
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Synthesis
formation of new
substances
Energetics
thermodynamics
of chemical
change (uptake
or release of
heat)
Dynamics
details of atom
rearrangements
Composition
and Structure
define the
substances
produced due to
Cx change
Chemistry is the study of substances;
their properties, structure, and the
changes they undergo.
19. Central Theme in Chemistry (The Forest or the Trees)
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realm macroscopic view microscopic view
composition formulas, mixtures
structures of solids,
molecules, and atoms
properties
intensive properties of
bulk matter
particle sizes, masses
and interactions
change (energetics)
energetics and
equilibrium
statistics of energy
distribution
change (dynamics)
kinetics (rates of
reactions)
mechanisms
20. Composition
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Pure Substance composed of only one
component, while Mixture, several.
Elements are monoatomic, Compounds,
polyatomic
Uniformity
Homogeneous - same properties in
different part of mixture
Heterogeneous – non uniform
Compound
Molecule
22. 22
Changes in Matter
Chemical Change
– properties of the original materials and products are not
the same.
- new substance is formed
eg. Heating Iron in moist air causes chemical reaction
(rusting)
Physical Change
-Reversible change in the state of material without altering
its composition
eg. Melting and freezing of water
23. Energy in Matter
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Gottfried Leibniz (1646-1716)
-suggested the distinction between vis viva (“live
energy”) and vis mortua (“dead energy”) which
became kinetic and potential
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Kinetic energy is associated with the motion of an object; a
body with a mass, m, and moving at a velocity, v, possesses
the kinetic energy 1/2 mv2. This "v-squared" part is
important; if you double your speed, you consume four
times as much fuel (glucose for the runner, gasoline or
electricity for your car.
Potential energy is energy a body has by virtue of its location
in a force field — a gravitational, electrical, or magnetic
field. For example, if an object of mass m is raised off the
floor to a height h, its potential energy increases by mgh,
where g is a proportionality constant known as
the acceleration of gravity. Similarly, the potential energy
of a particle having an electric charge q depends on its
location in an electrostatic field.
25. 25
Kinetic and potential energy are freely interconvertible
Pick up a book and hold it above the table top; you
have just increased its potential energy in the
force field of the earth's gravity. Now let it
drop. Its newly-acquired potential energy begins
to re-appear as kinetic energy as it accelerates
downward at a velocity increasing by 9.8 m/sec
every second (9.8 m sec–2 or 32 ft sec–2). At the
instant it strikes the surface, the potential
energy you gave supplied to the book has now
been entirely converted into kinetic energy.
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And what happens to that kinetic energy
after the book stops moving? It is still
there, but you can no longer see its effect;
it has now become dispersed as thermal
kinetic energy ("heat") into the molecules
of the book, the table top, and, ultimately,
into the surroundings, including the air.
27. The Chemistry Connection
Atoms and molecules are the principle
actors of thermal energy, but they possess
other kinds of energy as well that plays a
major role in chemistry.
The strength of a chemical bond
increases as the potential energy
associated with its formation
becomes more negative
Bond Energy
Chemical Energy
Molecules are vehicles both for storing and
transporting energy, and the means of converting it
from one form to another when the formation,
breaking, or rearrangement of the chemical bonds
within them is accompanied by the uptake or release
of energy, most commonly in the form of heat.
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Atoms are indivisible,
those of a given
element are identical,
and compounds are
combinations of
different atom types
Discovered electrons
in atoms(1897), for
which he won a Nobel
Prize – “Plum pudding”
model. Atoms as
composed of
electrons scattered
throughout a
spherical cloud of
positive charge
Fired positively
charged alpha
particles at a thin
sheet of gold foil.
Most passed with little
deflection, but some
deflected at large
angles.
Modified Rutherford’s
model of the atom by
stating that electrons
moved around the
nucleus in orbits of
fixed sizes and
energies. Electron
energy is quantized;
electrons cant occupy
values of energy
between fixed energy
levels.
Stated that electrons
do not move in set
paths around the
nucleus, but in waves.
It is impossible to
know the exact
location of the
electrons; instead, we
have ‘clouds of
probability’ called
“orbitals” in which
electron can be found
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The planetary model
1867 – Thompson demonstrated that all atoms
contain units of negative electrical charge.
1909 – Ernest Rutherford (Thompson’s student)
distrusted the “plum pudding” model (as he called it)
and soon put it to rest; Alpha-ray bombardment
experiment showed that nearly all the mass of atom
is concentrated in an extremely small body called
“nucleus”– carried out by his students, Hans Geiger
and Ernest Marsden.
The planetary model describes that electron spins
around in the nucleus by a balanced centrifugal force
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Bohr’s Model
Niels Bohr – planetary model could be saved if
one new assumption were made: certain
“special states of motion” of the electron,
corresponding to different orbital radii, would
not result in radiation, and could therefore
persist indefinitely without the electron falling
into the nucleus.
34. Modern Atomic Theory
Although the word atom comes from a Greek word that
means “indivisible,” we understand now that atoms
themselves are composed of smaller parts called subatomic
particles.
The first part to be discovered was the electron, a tiny
subatomic particle with a negative charge. It is often
represented as e−, with the right superscript showing the
negative charge. Later, two larger particles were discovered.
The proton is a more massive (but still tiny) subatomic
particle with a positive charge, represented as p+.
The neutron is a subatomic particle with about the same
mass as a proton but no charge. It is represented as either n
or n0. We now know that all atoms of all elements are
composed of electrons, protons, and (with one exception
Protium) neutrons.
Name Symbol
Mass
(approx.; kg)
Charge
Proton p+
1.6 × 10−27
1+
Neutron n, n0
1.6 × 10−27
none
Electron e−
9.1 × 10−31
1−
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Atomic Number
The atomic number or
proton number (symbol Z) of a chemical
element is the number of protons found in
the nucleus of every atom of that
element. The atomic number uniquely
identifies a chemical element. It is
identical to the charge number of the
nucleus
Atomic mass VS Atomic weight
39. 39
From Orbits to Orbitals
-From Bohr to de Broglie showed that electron should have wavelike properties of its own.
-Summerfeld assumed that orbits are elliptical instead of circular.
The one developed by Schrödinger is the most easily visualized . Schrödinger started with the
simple requirement that the total energy of the electron is the sum of its kinetic and potential
energies:
E =
𝑚𝑣2
2
+
−𝑒2
𝑟
Kinetic
energy
Potential
energy
40. 40
Why doesn't the electron fall into the nucleus?
The answer comes from the Heisenberg Uncertainty Principle, which says that a quantum
particle such as the electron cannot simultaneously have sharply-defined values of
location and of momentum (p=mv) (and thus kinetic energy).
Electron Well
The smaller the box, the more exactly will we know the location
of the electron. But as the box gets smaller, the uncertainty in
the electron's kinetic energy will increase. As a consequence of
this uncertainty, the electron will at times possess so much
kinetic energy (the "confinement energy") that it may be able
to penetrate the wall and escape the confines of the box.
Tunneling/Tunnel Effect
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Quantum Numbers
Orbitals
Instead of paths as describe in the planetary model, it is more
appropriate to indicate locations in the space around the nucleus at
which the probability of finding the electron has higher values. The
electron retains its particle-like mass and momentum, but because the
mass is so small, its wavelike properties dominate. The latter give rise
to patterns of standing waves that define the possible states of the
electron in the atom.
n describes the most probable distance of the electrons from the nucleus,
the larger the number n is, the farther the electron is from the
nucleus, the larger the size of the orbital, and the larger the atom is. n can
be any positive integer starting at 1, as n=1 designates the first principal
shell (the innermost shell).
42. 42
Modern Quantum Theory states that various allowed states of
existence of electron in H atom correspond to different standing
wave patterns.
1.Instead of indicating displacement of a point on a vibrating string,
the electron waves represent the probability that an electron will
manifest itself (appear to be located) at any particular point in
space.
2.The electron waves occupy all three dimensions of space, whereas
guitar strings vibrate in only two dimensions.
*each wave pattern is identified by an integer
n – principal quantum number.
*n= peaks (amplitudes/antinodes
*more peaks = more energy
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Significance of n
In the Bohr model, each value of n corresponded to an orbit of a different radius. The
larger the orbital radius, the higher the potential energy of the electron.
This physical interpretation of the principal quantum number as an index
of the average distance of the electron from the nucleus turns out to be
extremely useful from a chemical standpoint, because it relates directly to
the tendency of an atom to lose or gain electrons in chemical reactions.
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Orbital Shapes
Orbitals have been given names, which are usually given
in the form:
where X is the energy level corresponding to
the principal quantum number n; type is a lower-case
letter denoting the shape or subshell of the orbital,
corresponding to the angular quantum number ℓ;
and y is the number of electrons in that orbital.
For example, the orbital 1s2 (pronounced as the
individual numbers and letters: "'one' 'ess' 'two'") has
two electrons and is the lowest energy level (n = 1) and
has an angular quantum number of ℓ = 0, denoted as s.
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Summary
• Properties of Matter (Physical and Chemical)
• Separation process
• Atomic model
• Charges (elementary particles)
• Electron
46. References
Lower, S. (2021, March 4). Introduction to Chemistry. Retrieved March 19, 2021, from
https://chem.libretexts.org/@go/page/3558
Silberberg, M. (2012). Principles of general chemistry. McGraw-Hill Education.
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