Download Unit 2 Notes Atomic Structures

Unit 2- Early Theories
Early Scientists: (450 B.C.)
Earth, Water, Air, and Fire: The Four States of Matter
The ancient Greek philosophers’ curiosity sparked the interest of scholarly thinking.
They speculated about the nature of matter, and formulated explanations of matter based on their
own life experience. Therefore they believed that there are four
elements that everything is made up of: earth, water, air,
and fire. This theory waslater be supported and added to by
Aristotle who was more beloved and therefore able to persuade
people from believing in Democritus atoms. (Aristotle also
suggested that there was a fifth element, aether, because it
seemed strange that the stars would be made out of earthly
elements. He would be surprised to learn that they are in fact
made up of many elements found on earth, and are so hot they
could be said to be on fire all the time!) According to Aristotle
atoms could not exist because they would have to move
through empty space, and empty space could not exist. These
idea that these four elements earth, water, air, and fire - made up all matter was the cornerstone
of philosophy, science, and medicine for the next two thousand years. Everything visible was
made up of some combination of earth, water, air, and fire
Democritus: (460-370 B.C.)
Democritus was an ancient Greek philosopher who is an influential pre-Socratic
philosopher and pupil of Leucippus, who formulated what, is thought to be the first atomic
theory. Some people consider him to be the father of modern science.
Democritus claimed that everything is made up of what he called atomos, later becoming
the English word atoms. His ideas were based on reasoning rather than science. He reasoned that
if you cut a stone in half, each half had the same properties as the original stone. He theorized
that there are an infinite number of atoms and kinds of atoms, which differ in shape, and size.
Through reasoning he stated that if you continued to cut the stone into smaller and smaller
pieces, at some point you would reach a piece so tiny that it could no longer be divided.
Using analogies from our senses, you give us an image of an atom that distinguished
them from each other by their shape, size, and the arrangement of their parts.. Your model (or
The Democritean atom) is an inert solid that interacts with other atoms mechanically.
Antoine-Laurent Lavoisier:
He is recognized as the father of modern chemistry. He believed that matter was neither
created nor destroyed in a chemical reaction, and sought to prove that hypothesis. He performed
some of the first quantitative chemical experiments. He studied the thermal decomposition of
mercury (II) oxide, which is a powdery red solid. When the solid is heated it reacts to form
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silvery liquid mercury and colorless oxygen gas. He intelligently performed the reaction in a
closed container so that the gas could not escape. Curious he did experiments with many other
gases including hydrogen and oxygen. Upon inserting a match in the glass container containing
the two, he observed the formation of water. In conducting other experiments you observed that
when new substances were made the mass from the original substances were the same as the new
substances. The data from his experiments led to the making of the law of conservation of mass.
The law of conservation of mass states that mass is neither created nor destroyed in a chemical
reaction.
Joseph Proust:
Proust was a French chemist who lived in the 1700s and worked most of his life as a
teacher. Although he had no understanding of the atom, he believed that substances always
combined in definite proportions. His significance to the modern atomic model however came
by analyzing different sources of compounds; he found that they always contained the same ratio
by weight of their elements. Such as when reacting hydrogen with oxygen, he noticed that water
is always composed of 11% hydrogen and 89% oxygen by mass. Also table salt always
contained 1.5 times as much chlorine as sodium. This led to the Law of Definite Proportions.
The Law of Definite Proportions states that the ratio by mass of the elements in a chemical
compound is always the same regardless of the source of the compound.
John Dalton: (1803)
John Dalton, an observer of weather and discoverer of color blindness among other
things, was the first scientist to explain the behavior of atoms in terms of the measurement and
weight.
By studying Democritus’s work Dalton became fascinated with atoms and sought to expand his
theory. He believed that different atoms or elements could be distinguished by their weight.
While working on your theory you discovered the law of multiple proportions which states that
when combining two or more elements to form a chemical compound, the elements are always in
the smallest whole number ratios.
This ground breaking research lead to Dalton’s Atomic Theory which had 5 basic principles:
1. All matter is made up of tiny indivisible spheres (atoms).
2. All atoms of one element are exactly alike, but they are different from atoms of other
elements.
3. Atoms of different elements have different physical and chemical properties.
4. Atoms of different elements combine in simple whole number ratios to form compounds.
5. Atoms cannot created or destroyed in a chemical reaction.
Your billiard ball model of the atom was the first model that was widely accepted as what we
now call atoms. Even though your ideas are similar to Democritus’s people accepted your ideas.
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Unit 2- Subatomic Particles
1. The electron
a. _______________ Tube experiment in 1897
i. Completed by _______________________
ii. Atoms not neutral spheres, composed of _____________ particles
iii. Electrons (_________)
iv. Calculated mass to be ________________________ grams
Cathode Ray Tube
Thompson’s Plum Pudding Model of the atom
b. __________________ oil drop experiment
i. Used x-rays to place a charge on ___________droplets
ii. Applied an exact voltage to_______________ charged oil droplets
iii. Used this to determine the exact charge of an ______________ 1.6 x 10-19 C.
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2. Eugen Goldstein
i. Observed rays in a ______________tube traveling from the ___________to the
cathode.
ii. These were deflected towards the __________________plate.
iii. Protons! (_______) =______________________grams
iv. Elements seemed to be comprised of an even number of electrons and protons.
3. Neutrons
a. Not discovered until 1932 by _______________ _________________
i. ______________charged particles
ii. (n0) = ____________________ grams
iii. Accounts for _________________- atoms of an element that are chemically
alike but differ in _______________.
b. Isotope notation:
𝑦
𝑧𝑋
i. ______ is the atomic symbol _________is the mass number, and _____is the
atomic number
ii. Atomic number = number of ___________________
iii. In a neutral atom the number of protons equals the number of ____________
iv. Mass number = number of ___________+_____________
v. Atomic Mass unit (_______) is equal to the mass of __________ proton or
neutron
1. Example:
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Nuclear Stability
1. How elements are created
a. Elements from 1-92 were _______________ created.
b. All elements from 2-26 were formed through _________________by stars
c. All others are created through nuclear reactions.
2. Nuclear Reactions
a. Involve a ____________ in the _________________ of an atom
b. Occur because the nucleus of an atom is ____________________
i. Inside an atom
1. Two subatomic particles make up the nucleus the _______________
and the ________________
2. As the number of protons increase, there are more _______________
within the nucleus.
3. _____________________ help by acting as buffers to decrease the
repulsive _________________ between protons.
3. Stability of the nucleus
a. Whether a nucleus of an atom is stable or unstable depends on the ____________ of
protons to neutrons in the nucleus.
b. This is called the N: Z ratio where N is the number of _____________ an isotope has and
Z is the number of __________________ an isotope has.
i. Isotopes of the same element have the same number of _______________ and
different number of ____________________.
ii. For element > # 20 the ratio of N:Z needs to be ___________ for the isotope to
be stable.
iii. For elements 20-83 the ratio of N:Z needs to be ______________for the isotope
to be stable.
1. Example:
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a.
C and 14C
b.
130
Xe and
141
Xe
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iv. The graph shows the band of ______________, if it is not with in the band then
the nucleus is unstable and will __________________ to a new element.
4. Types of nuclear decay
a. Alpha emission
i. Occurs when there are too many ______________ in the nucleus
ii. An alpha particle is emitted
1. An _______________ particle is the nucleus of a helium atom without
any electrons = ___________________
iii. Example:
b. Beta emission
i. Occurs when there are too many ___________________ in the nucleus
ii. A neutron _______________ into a proton and a beta particle is ejected from
the nucleus.
1. A beta particle is an ____________ = −10𝛽 or −10𝑒
iii. Example:
c. Gamma Emission
i. Gamma is a high ________________ electromagnetic wave
ii. Is emitted in _____________decay processes
1. Also known as gamma radiation = _______________
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Half Life
1. The half-life of an element is the time it takes for _____________ of the quantity of that
element to _________________.
a. The _________________ of the element remaining is _____________________ after
each successive half-life is reached.
b. Ex. The half-life of 146C is 5,730 years. If you start with 100.00 grams of 146C, after
17,190 years how much of 146C is left?
Mass Left
Years Passed
Half lives
2. Carbon dating:
a.
While an organism is alive it is constantly replacing the carbon in its body with
_________________ obtained from the food it ate or absorbed.
b. While alive the ratio of Carbon-12 to Carbon-14 stays essentially
_______________________.
i. When dead the Carbon-14 in organisms begins to undergo ____________decay.
ii. By measuring the amount of _________________ left, in dead organisms we
can calculate how much ________________ has elapsed since the organism
died.
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Rutherford and Bohr Models
1. Ernest __________________
a. Conducted _____________ foil experiment in 1911
i. Shot __________ particles at a sheet of gold ___________ surrounded by a
fluorescent screen.
ii. Expected the alpha particles to go straight ___________________ the atoms
based on J.J Thompsons plump pudding model of the atom.
Rutherford’s Gold Foil Experiment
iii. Concluded from the experiment that ____________ are
mostly_________________ space and with a ____________ charged core , the
_____________________.
b. Nuclear Model
i. Nucleus containing _______________and _______________
ii. Surrounded by mostly empty space containing _______________.
iii. The atom is mostly empty space with a center ______________and
___________________that are in _______________ in the outer part of an
atom.
iv. When two atoms come near each other, it is the __________________ that
interact.
Rutherford’s Nuclear Model of the Atom
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2. Niels________________
a. Proposed that electrons must have enough _______________ to keep them in
___________________motion around the nucleus.
b. Electrons orbit the nucleus in orbitals of a _______________energy
i. _____________________ can only circle the nucleus at certain
_______________away from the nucleus; these are called _____________ or
energy levels.
Bohr’s Planetary
Model of the
atom
1. Each __________________has a certain amount of
_____________________associated with it.
a. Closer to the nucleus = a____________ orbit =
______________ energy
b. Further away from the _______________= a _________orbit =
______________energy
2. ________________- the amount of energy needed to
________________to a new energy level.
a. Electrons cannot be _______________ levels
b. Proposed by Max ________________
How to find the number of valence electrons: The Bhor model of the atom:
To draw the Bohr model of the atom: example: Ne
1. Start by placing the correct number of protons and neutrons of the element in the center
a. Protons are found from the atomic number.
b. Neutrons are found from subtracting the atomic number from the mass number of the
most stable isotope.
2. Add enough energy levels for the element in question
a. You can figure this out by counting the number of rows on the periodic table.
b. Each energy level has a specific number of electrons that can go into it.
i. First = 2 electrons
ii. Second = 8 electrons
iii. Third = 18 electrons
iv. Fourth = 32 Electrons
You try:
O
S
K
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3. _______________ _______________ Model – ____________ of ____________ based on the
______________ properties of an ___________________
a. Deals with the ___________________ of finding an _____________ orbiting an
________
b. ________________
i. _____________ region around the _______________ where an
___________can be found
ii. Forms a __________around the _________________
iii. _____________and _____________ of the cloud depends on the ___________
___________ of the ____________
iv. _______________ can exist _______________ in the ____________, but
________between orbitals.
4. Atomic Orbitals/ Quantum Numbers
a. Ewin _______________ developed an _______________that describes
the________________ of finding the position of an ___________________.
b. Describes the _______________ of an ________________ in an _____________
i. ___________________Quantum Number (______)
1. The _________ ______________ the _____________ occupies
2. ______________ numbers ____________
3. The ______________ the number is, the _______________ the
_________ is away from the_________________
4. ___________ is the ______________ number of_____________ in the
__________ ____________
5. Contains _____________ equal to _______
ii. ____________ Quantum Number (_______)
1. The _______________ of________
2. Defines the ____________of the ____________
3. _________is an _______________ from _______________
4. Example- if n = 3 what are all possibilities for 𝓵
5. Each _____________ is expressed as a ____________ s,p,d,f
𝓵 = 0 (_______)
Picture of s
a. _________sublevel
b. _____________
𝓵=1 (_____)
a. ______ sublevels
Pictures of p
b. ______________
𝓵 =2 (_______)
a. __________ sublevels
6. 𝓵 = 3 (______________)
a. ______________sublevels
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5. Electromagnetic Spectrum
a. Total ________________ of ______________________ radiation
10
24
10
22
20
10
rays
-16
-14
10
10
10-12
Wavelength (m)
10
18
10
rays
10-10
16
10
14
rays
10-8
10
12
IR
10-6
400 nm
10-4
10
8
6
10
10
10
Microwaves Radio Waves
10-2 100
10-2
Frequency (Hz)
10
102
100
Long Radio Waves
104
106
108
4
700nm
vi. Wavelength (______) – Distance __________ corresponding _________
on adjacent waves
vii. Frequency (__________) – ___________of ________ that pass by a point
in a certain _____________ of time.
6. ________________ can be described as _____________or _____________
a. ______________states – when____________ are boosted to ___________
energy levels
b. _____________________state – the _____________ energy level
c. When _____________ go to a ________________ energy state they __________
a _______________ of energy.
viii. This _____________ is in the form of ______________, called a
____________.
7. _____________ Uncertainty Principle
a. _____________Physicist
b. Determined it’s ___________ possible to measure both _____________and the
___________of an ______________ at the same ___________.
8. Bright light emission spectrum.
a. Certain ____________ levels emit certain___________ when an __________
falls from them.
b. Each ____________ has a particular ____________ associated with it and so emit
a specific _____________ of _______________.
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1. Electron configurations
a. Written notation to show how _____________ are distributed within ________________
1s2
b. Examples:
i. Nitrogen
ii. Potassium
c. Exceptions:
i. Cr
ii. Cu
d. Nobel Gas configurations:
i. Potassium
ii. Bromine
e. Rules for orbital diagrams:
i. Aufbau Principle –_______________ must occupy the _____________energy
level ______________.
ii. Hund’s Rule - Orbital's of ____________energy will occupy an _________
______________ before ___________________ occurs.
iii. Pauli ______________Principle – no two ______________ can have all
_________quantum numbers the ______________.
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How did you organize your candy?
1. History of the periodic table
a. Demitriy ________________
i. Realized that the ________________ and _________________properties of the
______________________ repeated in an __________________ way when he
organized the elements according to increasing _______________ ___________.
ii. Elements with ________________properties were placed in the ____________
horizontal _____________.
iii. Table showed that ____________________ of elements ____________ in an
__________________way from row to row.
iv. Mendeleev’s table left some ________________ spaces; this suggested that there
were___________________ that had not yet been _________________.
v. Using the table Mendeleev could ______________ the properties of these
unknown elements.
Properties of Eka- Aluminum (Germanium)
Property
Predicted (1869)
Atomic mass
72 amu
Color
Dark gray
Density
5.5 g/ml
Melting point
Very high
Formula of oxide
EsO2
Density of oxide
4.7 g/ml
Oxide solubility in HCl
Slight
Formula of chloride
EsCl4
Actual (1886)
Gray-white
5.32 g/ml
937 0C
GeO2
4.70 g/ml
none
GeCl4
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b. ______________________- tendency to ___________at regular ______________.
i. Mendeleev was so confident in ________________ that he placed some elements
in groups with others of _______________ properties even though this
__________________ did not go strictly by _____________ ____________.
c. Henry _________________
i. Organized his ______________table by _____________ _______________.
2. Modern Periodic Table
a. __________________ Law –_______________ and _________________ properties of
elements _______________ in a regular _______________ when they are arranged by
_______________ atomic number.
3 Undiscovered Elements
1.
2.
3.
8. Family Characteristics
a) Group 1 (Alkali metals)
i) Soft and highly reactive.
ii) Alkali
(1) Produce alkaline (basic) solutions
(2) Slippery to the touch
iii) Metal
(1) Malleable
(3) Conducts heat and electricity
(2) Ductile
(4) Luster
iv) Have 1 electron in highest energy level.
b) Group 2 (Alkaline earth metals)
i) Harder and more dense than alkali metals.
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ii) Not as reactive as alkali metals.
iii) Contain 2 electrons in their highest energy level.
c) Group 3 - 12 (Transition elements)
i) All are metals.
ii) Not as reactive as alkali or alkaline earth metals.
iii) Electron configuration can change within a group in order to better stabilize the atom.
d) Lanthanide Series
– 71Lu
i)
58Ce
ii)
Rare earth elements.
iii) Most are radioactive
e) Actinide series
i)
ii)
90Th
– 103Lr
All are radioactive.
iii) Have unstable electron configurations.
f) Group 13 – 18 (Main block elements)
i) Represent a wide range of chemical and physical properties.
ii) Contain metals, metalloids, non-metals and noble gases.
g) Group 17 (Halogens – salt formers)
i) Readily combine with alkali metals or alkaline earth metals to form a “salt”
ii) Most reactive non-metals.
iii) Have 7 electrons in the highest energy level.
h) Group 18 (Noble Gases)
i) The group of Noble gases were originally proposed by Strutt and Ramsey when they
discovered the element Argon.
ii) Have a full s and p orbitals
iii) Stable configuration, or, resists change (inert).
i) Hydrogen (Own family)
i) Behaves like no other element.
ii) Has only one electron.
iii) Rare on earth in its free state, usually found in combination with other atom(s).
(1) Ex. H2O, CH3CH2OH, CH3CH2CH2CH2CH2CH2CH2CH3
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8. Octet Rule- in order for an element to be _____________ it must possess full ____ and
______orbitals
a. Have _________ electrons in its _______________energy level!
b. Elements will react _________________, or nuclearly to achieve this ________.
Periodic Trends
1. Atomic Radius- ____________ of an ________________
a. _________________of the distance between the ________________ of
_______________elements
i. Diatomic ________________- elements that e_________ in nature as a
______________
1. _____________ diatomic elements
a.
b. _______________ down a group
i. The more _____________ ______________ there are the _____________
the atom is.
c. _______________________ from left to right across a period
i. ________________ effect- ________________ of the attraction between a
__________________and its ____________
electrons due to the ______________ effect of the
______________electrons.
2. Ionization Energy
a. ___________- an atom that has ____________ or _____________electron(s)
giving it a __________________
i. ______________- an ion that has _______________ electron(s)
1. Have a _________________charge
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ii. _______________- an ion that has ____________ electron(s)
1. Have a _________________charge
b.________________ electrons- electrons in the ___________________energy _________of an
atom.
i.
Responsible for _______________of the chemical ______________ between
atoms
ii. Electrons _______________ or _________________will be ______________ electrons
How to find the number of valence electrons: The Bhor model of the atom:
To draw the bohr model of the atom: example: Ne
3. Start by placing the correct number of protons and neutrons of the element in the center
a. Protons are found from the atomic number.
b. Neutrons are found from subtracting the atomic number from the mass number of
the most stable isotope.
4. Add enough energy levels for the element in question
a. You can figure this out by counting the number of rows on the periodic table.
5. Figure out how many electrons can go in each energy level.
a. 2n2 rule
6. Add as many electrons as are in the element filling the energy levels starting closest to
the nucleus.
a. The number of electrons is equal to the number of protons.
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b. ________________ energy- energy required to __________________an
________________from an element.
i. ________________ down a _________________
1. ________________ that are held more tightly to the__________
will be _______________________ to remove
a. The _________________ an atom is the __________
energy required to______________an _____________.
ii. _______________ from left to right in a ________________
a. The _________________an atom is the
___________energy required to ___________an electron.
3. ______________________- the tendency of an ___________________ to attract
__________________ to itself when forming a ______________________.
a. The higher the__________________, the more likely an ___________ is to attract
______________.
i. _________ has the highest at _________________
b. ________________ down a _________________
i. The _____________________ the ________________ are held by the ______________,
the greater the ____________________ is.
ii. As the_____________ gets _____________ the__________________ gets
______________________.
c. _______________________ from left to right in a _______________.
i. As the atomic_______________
gets________________ the
____________________gets
___________________.
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Martian Periodic Table
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Element List
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
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U
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