KADUNA STATE

UNIVERSITY
Faculty of Science
Department of Biochemistry
Group 9 GST 203 Presentation
Topics: Early atomic and molecular theories of physics

 The break down of Classical Physics

 Modern Physics
 Relativity
 Nuclear Physics
 Quantum Theory

S/N Names Matric number

1 Jimmy O. Godday KASU/20/BCH/1210
2 Ruth Haruna KASU/20/BCH/1073
3 Martha Omowumi Enechukwu KASU/20/BCH/1080
4 Aminu khadija Ahmad KASU/20/BCH/1097
5 Sani Zuhair KASU/20/BCH/1050
6 Giwa Akuso Monica KASU/20/BCH/1095
7 Fadila Umar KASU/20/BCH/1189
8 Ahmad Sulaiman KASU/20/BCH/1054
9 Bashir Aisha Mustapha Transfer
10 Fatima Mahmud KASU/20/BCH/1107
11 Sani Safinatu Yaro KASU/20/BCH/1133
 12 Najib Lawal KASU/20/BCH/1211
13 Lord-Williams John KASU/20/BCH/1170

TABLE OF CONTENTS
I. The early atomic and molecular theories of Physics
 John Dalton’s atomic theory
 Kinetic molecular theory
 Max Planck’s theory
 Ernest Rutherford’s nuclear model
II. Classical physics
 The discovery of electromagnetism
III. Modern Physics
IV. The development of relativity
V. Nuclear Physics
VI. Quantum theory
 The development of the quantum world
 The emergence of quantum mechanics
VII. Reference (s)
 I. Early Atomic and Molecular Theories of
Physics.

Early atomic and molecular theories of physics have a rich history that
dates back to the ancient Greeks. Here are some of the key theories
and ideas that have shape our understanding of the atomic and
molecular world.
Atomic theory has evolved since ancient times. The hypothesis of Greek
scholars has become the basis of analysis by scientists. They have done
a lot of discoveries and theories regarding the atom. Moreover, it
derives from the Greek word “atomos,” which means indivisible.
Atom Definition
The smallest particle of an element, which may or may not have an
independent existence but always takes place in a chemical reaction is
called an atom. An atom is defined as the smallest unit that retains the
properties of an element. An atom is composed of sub-atomic particles
and these cannot be made or destroyed. All atoms of the same element
are identical and different elements have different types of atoms.
Chemical reactions occur when atoms are rearranged.
Atoms consist of three fundamental types of particles, protons,
electrons and neutrons. Neutrons and protons have approximately the
same mass and in contrast to this the mass of an electron is negligible.
A proton carries a positive charge, a neutron has no charge and an
electron is negatively charged. An atom contains equal numbers of
protons and electrons and therefore overall an atom has no charge. The
nucleus of an atom contains protons and neutrons only, and therefore
is positively charged. The electrons occupy the region of space around
the nucleus. Therefore, most of the mass is concentrated within the
nucleus.
The center of the atom is called the nucleus. The nucleus contains
neutrons and protons that give an atom its weight and positive charges.
A neutron carries no charge and has a mass of one unit. A proton
carries a single positive charge and also has a mass of one unit, The
atomic number of an element is equal to the number of protons or
positive charges in the nucleus. The atomic weight of an element is
determined by combining the total number of protons and neutrons in
the nucleus. An electron carries a single negative charge. If an atom of
an element is to have zero charge, it must have the same number of
electrons as protons. These electrons are arranged in orbits around the
nucleus of the atom like the layers of an anion.
What is a Molecule?
A molecule is defined as the smallest unit of a compound that contains
the chemical properties of the compound.
Molecules are made up of groups of atoms. Describing the structure of
an atom, an atom is also sub-divided into smaller units. Protons,
electrons, and neutrons are sub-particles of an atom. The protons and
neutrons are contained inside the nucleus of the atom and electrons
revolve around the nucleus.
Protons are positively charged particles whereas electrons are
negatively charged particles. Neutrons do not carry any charge. So we
can say that the nucleus is positively charged due to the presence of
protons. The nucleus is a bulk mass at the center of an atom. Atoms are
largely vacant.

 Dalton’s Atomic Theory (1804)

Dalton’s modern atomic theory, proposed around 1804, is a

fundamental concept that states that all elements are composed of
atoms. Dalton studied the weights of various elements and compounds.
He noticed that matter always combined in fixed ratios based on
weight, or volume in the case of gases. Dalton also observed that there
could be more than one combination of two elements.
From his own experiments and observations, as well as the work of his
peers, Dalton proposed a new theory of the atom. This later became
known as Dalton’s atomic theory.
The general tenets of this theory are as follows:
1. All matter is composed of extremely small particles called atoms.
2. Atoms of a given element are identical in size, mass, and other
properties. Atoms of different elements differ in size, mass, and other
properties.
3. Atoms cannot be subdivided, created, or destroyed.
4. Atoms of different elements can combine in simple whole number
ratios to form chemical compounds.
5. In chemical reactions, atoms are combined, separated, or
rearranged.
Limitations of Dalton’s Atomic Theory
 1. It does not account for subatomic particles: Dalton’s atomic
theory stated that atoms were indivisible. However, the
discovery of subatomic particles (such as protons, electrons,
and neutrons) disproved this postulate.
2. It does not account for isotopes: As per Dalton’s atomic
theory, all atoms of an element have identical masses and
densities. However, different isotopes of elements have
different atomic masses (Example: hydrogen, deuterium,
and tritium).
3. It does not account for isobars: This theory states that the of
the atoms of two different elements must differ. However, it
is possible for two different elements to share the same
mass number. Such atoms are called isobars.
4. Elements need not combine in simple, whole-number ratios
to form compounds: Certain complex organic compounds do
not feature simple ratios of constituent atoms.
5. The theory does not account for allotropes: The differences
in the properties of diamond and graphite, both of which
contain only carbon, cannot be explained by Dalton’s atomic
theory.

 Kinetic Molecular Theory

The kinetic molecular theory is a theoretical model that describes the
molecular composition of the gas in terms of a large number of
submicroscopic particles which includes atoms and molecules.The
theory explains that gas pressure arises due to particles colliding with
each other and the walls of the container. It describes an ideal Gas,
PV=nRT.
Kinetic Molecular Theory Of Gases
 The gases are made up of a large number of molecules and they are
flying in a random direction at a certain speed. By knowing the value of
velocity or the internal energy of gas molecules.
The Kinetic Molecular Theory Postulates
The experimental observation about the behavior of gases discussed so
far can be explained with a simple theoretical model known as the
kinetic molecular theory. This theory is based on the following
Postulates or assumption:
1. The particles in a gas are, random motion;
2. The combined volume of the particles is negligible;
3. The particles exert no forces on one another;
4. Any collisions between the particles are completely elastic;
5. The average kinetic energy of a collection of gas particles depends on
the temperature of the gas and nothing else.

How kinetic molecular theory explains the gas

1- The link between P and n
2- Amonton's Law
3- Boyle's Law
4- Charle's Law
5- Dalton's Law of partial pressure
6- Graham's Law of diffusion and emission

 Planck’s quantum theory

According to Planck’s quantum theory, different atoms and molecules
can emit or absorb energy in discrete quantities only. The smallest
amount of energy that can be emitted or absorbed in the form of
electromagnetic radiation is known as quantum.
The energy of the radiation absorbed or emitted is directly proportional
to the frequency of the radiation.
Planck’s constant, (symbol h), fundamental physical constant
characteristic of the mathematical formulations of quantum mechanics,
which describes the behavior of particles and waves on the atomic
scale, including the particle aspect of light. The German physicist Max
Planck introduced the constant in 1900 in his accurate formulation of
the distribution of the radiation emitted by a blackbody, or perfect
absorber of radiant energy (see Planck’s radiation law). The significance
of Planck’s constant in this context is that radiation, such as light, is
emitted, transmitted, and absorbed in discrete energy packets, or
quanta, determined by the frequency of the radiation and the value of
Planck’s constant. The energy E of each quantum, or each photon,
equals Planck’s constant h times the radiation frequency symbolized by
the Greek letter nu, ν, or simply E = hν. A modified form of Planck’s
constant called h-bar (ℏ), or the reduced Planck’s constant, in which ℏ
equals h divided by 2π, is the quantization of angular momentum. For
example, the angular momentum of an electron bound to an atomic
nucleus is quantized and can only be a multiple of h-bar.
The dimension of Planck’s constant is the product of energy multiplied
by time, a quantity called action. Planck’s constant is often defined,
therefore, as the elementary quantum of action. Its value in metre-
kilogram-second units is defined as exactly 6.62607015 × 10-³⁴ joule
second.
  Rutherford Model
Ernest Rutherford (1871 – 1937) was a British experimental physicist
best known for developing a model of the atom that contained a
central nucleus of positive charge surrounded by orbiting electrons. His
model corrected for some shortcomings in previous atomic models and
laid the groundwork for a better understanding of atomic structure and
properties.
Rutherford’s model was the first to introduce the concept of an atomic
nucleus. This novel idea accounted for the sparse distribution of electric
charges that was revealed in Rutherford’s famous gold foil experiment.
The Rutherford model and its immediate successor, the Bohr model,
changed the conception of the atom for decades until quantum
mechanics revolutionized atomic theory altogether.
Definition of the Rutherford Model
In many ways, the Rutherford model of the atom is the classic model of
the atom, even though it’s no longer considered an accurate
representation. Rutherford’s model shows that an atom is mostly
empty space, with electrons orbiting a fixed, positively charged nucleus
in set, predictable paths.
This model of an atom was developed by Ernest Rutherford, a New
Zealand native working at the University of Manchester in England in
the early 1900s. Rutherford spent most of his academic career
researching aspects of radioactivity and, in 1908, won the Nobel Prize
for his discoveries related to radioactivity. It was after this that
Rutherford began developing his model of the atom.
How Did Ernest Rutherford Change the Atomic Model?
The concept of an atom goes back to the ancient Greek philosopher
Democritus of Abdera (ca. 460 – 370 BCE). Democritus postulated that
everything consists of indivisible particles that he called atomos
(literally, ‘uncuttable’), and that there were different types of atoms for
different types of matter. Ancient Greek philosophers didn’t have the
technology to verify their hypotheses at the atomic scale, and generally
relied on reasoning alone, so Democritus’ atomic theory had no
substantial impact on science.
As chemistry began to emerge as a science in the 18th century,
however, a clearer picture developed of how different elements behave
and interact. Experiments began to provide evidence that the
properties of different elements and substances could be predicted
under controlled conditions. This led to the revival of atomic theories
that successively built upon one another, leading to more and more
accurate models.

II. Classical Physics

Classical physics, also known as Newtonian physics, refers to the
scientific understanding of the physical world that was developed
between the 17th and 19th centuries. Despite its age, classical physics
remains an important foundation for our understanding of the natural
world and continues to be used in a wide range of applications today.
However, the classical view of the physical world has been challenged
and modified over time due to the discovery of new phenomena and
the development of new theories.
Here are some key events that led to the breakdown of classical physics:
 The Discovery of Electromagnetism: The discovery of
electromagnetism in the 19th century challenged the classical view
of physics. Scientists observed that charged particles were subject
to forces that could not be explained by classical mechanics, and
that light could act both as a wave and as a particle.
 The Development of Relativity: The theory of special relativity,
developed by Albert Einstein in 1905, challenged the classical view
of space and time. Einstein showed that space and time were not
absolute and unchanging, but were relative to the observer.
 The Discovery of the Quantum World: In the early 20th century, the
discovery of the quantum world challenged the classical view of
physics. Scientists observed that the behavior of very small
particles, such as electrons, could not be explained by classical
mechanics or classical electromagnetism.
 The Emergence of Quantum Mechanics: In response to these
challenges, physicists developed a new theory of physics called
quantum mechanics. Quantum mechanics provides a
mathematical framework for understanding the behavior of
subatomic particles and the interactions between particles and
energy.
These developments and others led to the breakdown of classical
physics as the dominant view of the physical world and the emergence
of new theories and ideas that better described the complexities of the
natural world. However, classical physics continues to be used in many
everyday applications and remains an important part of the scientific
understanding of the physical world.
  Oersted & Electromagnetism
By the end of the 18th century, scientists had noticed many electrical
phenomena and many magnetic phenomena, but most believed that
these were distinct forces. Then in July 1820, Danish natural
philosopher Hans Christian Oersted published a pamphlet that showed
clearly that they were in fact closely related.
Oersted made the discovery for which he is famous in 1820. At the
time, although most scientists thought electricity and magnetism were
not related, there were some reasons to think there might be a
connection. For instance, it had long been known that a compass, when
struck by lightning, could reverse polarity. Oersted had previously
noted a similarity between thermal radiation and light, though he did
not determine that both are electromagnetic waves. He seems to have
believed that electricity and magnetism were forces radiated by all
substances, and these forces might somehow interfere with each other.
During a lecture demonstration, on April 21, 1820, while setting up his
apparatus, Oersted noticed that when he turned on an electric current
by connecting the wire to both ends of the battery, a compass needle
held nearby deflected away from magnetic north, where it normally
pointed. The compass needle moved only slightly, so slightly that the
audience didn’t even notice. But it was clear to Oersted that something
significant was happening.
Some people have suggested that this was a totally accidental
discovery, but accounts differ on whether the demonstration was
designed to look for a connection between electricity and magnetism,
or was intended to demonstrate something else entirely. Certainly
Oersted was well prepared to observe such an effect, with the compass
needle and the battery (or “galvanic apparatus,” as he called it) on
hand.
Whether completely accidental or at least somewhat expected, Oersted
was intrigued by his observation. He didn’t immediately find a
mathematical explanation, but he thought it over for the next three
months, and then continued to experiment, until he was quite certain
that an electric current could produce a magnetic field (which he called
an “electric conflict”).
On July 21, 1820, Oersted published his results in a pamphlet, which
was circulated privately to physicists and scientific societies. His results
were mainly qualitative, but the effect was clear–an electric current
generates a magnetic force.
His battery, a voltaic pile using 20 copper rectangles, probably
produced an emf of about 15-20 volts. He tried various types of wires,
and still found the compass needle deflected. When he reversed the
current, he found the needle deflected in the opposite direction. He
experimented with various orientations of the needle and wire. He also
noticed that the effect couldn’t be shielded by placing wood or glass
between the compass and the electric current.
The publication caused an immediate sensation, and raised Oersted’s
status as a scientist. Others began investigating the newly found
connection between electricity and magnetism. French physicist André
Ampère developed a mathematical law to describe the magnetic forces
between current carrying wires. Starting about a decade after Oersted’s
discovery, Michael Faraday demonstrated essentially the opposite of
what Oersted had found–that a changing magnetic field induces an
electric current. Following Faraday’s work, James Clerk Maxwell
developed Maxwell’s equations, formally unifying electricity and
magnetism.
 III. Modern Physics
Modern physics is based on the two major inventions of the early 20th
century. These are relativity and quantum mechanics. This kind of
Physics is based on what was known before then, i.e. Newton’s laws,
Maxwell’s equations, thermodynamics and termed as classical physics.
Modern physics is presenting the foundations and frontiers of today’s
physics. It is focusing on the domains like quantum mechanics;
applications in atomic, nuclear, particle, and also the condensed-matter
physics. Mainly it includes the special relativity, relativistic quantum
mechanics, Dirac equation and the Feynman diagrams, quantum fields
with general relativity. The aim of modern physics is to cover these
topics in sufficient depth.
Topics in Modern Physics
Various topics which form the core to the foundation of modern
physics are:
Atomic theory and atomic model
Black-body radiation
Franck–Hertz experiment
Geiger–Marsden experiment i.e. Rutherford’s experiment
Gravitational lensing
Michelson–Morley experiment
Photoelectric effect
Quantum thermodynamics
Radioactive phenomena in general
Perihelion precession of Mercury
Stern–Gerlach experiment
Wave-particle duality
Thermodynamics. Heat and temperature.
Vibrations and Waves Phenomena
Quantum Mechanics.
Important Discoveries in Modern Physics
Several experiments have marked the history and development of
Modern Physics. Among these, we may mention those who provided us
with a deeper understanding of the structure of matter and atoms.
Some such examples of these important discoveries are as given below:
In the year 1895, Wilhelm Röntgen discovered the existence of X-rays.
It is an invisible type of extremely penetrating radiation.
After a few years in the year 1900, the German physicist Max Planck
proposed that the energy-charged by the electromagnetic field and
having quantized values. It is the integer multiples of a minimum and
constant amount.
In the year 1905, through his theory of relativity, Albert Einstein
explained and showed that references which move at very high speeds.
This speed was close to the speed of light propagation, experience the
passage of time and the measurement of distances in different ways.
In the year 1913, Niels Bohr proposed that the energy levels of
electrons scattered around atomic nuclei are quantized. It means, their
energy is given by an integer multiple of a minimum value.
In the year 1924, the wave-particle duality, which was established by
physicist Louis De’Broglie, showed that anybody can behave like a
wave.
In the year 1926, Quantum Mechanics appeared. It was the result of
the work of physicists like Werner Heisenberg and Erwin Schröedinger.
Thus, modern physics was able to explore the nature of the microscopic
world and the great relativistic speeds. It also provides valuable
explanations for various physical phenomena that were, until then,
misunderstood.

IV. Relativity
Relativity is a theorem formulated by Albert Einstein, which states that
space and time are relative, and all motion must be relative to a frame
of reference. It is a notion that states’ laws of physics are the same
everywhere. This theory is simple but hard to understand.
It states:
• There is no absolute reference frame. One can measure
velocity if the object or momentum is only in relation to
other objects.
• The speed of light is constant irrespective of who measures
it or how fast the person measuring it is moving.
Albert Einstein’s Theory of Relativity encompasses two theories: Special
Relativity Theory and General Relativity Theory.
Special Theory of Relativity
Einstein first introduced this term in the year 1905. It is a theorem that
deals with the structure of space-time. Einstein explained this theory
based on two postulates –
• The laws of physics are the same for all, irrespective of the
observer’s velocity.
 • The speed of light is always constant regardless of the
motion of the light source or the motion of the observer.
This is the theory which laid the foundation of time travel. According to
Einstein, the rate at which time tics decreases with the increase of the
person’s velocity. But this is hard to notice as the decrease in time is
relatively very low compared to the increase in time. So, it can be
assumed that if you can equal the velocity of light, you will be in a
situation where time is still. This phenomenon is called Time Dilation.
There are other surprising consequences of this theory, such as –
• Relativity of simultaneity – two actions, simultaneous for
one person, may not be simultaneous for another person in
relative motion.
• Length Shrinking: Objects are measured and appear shorter
in the direction they are moving with respect to the
observer.
• Mass – Energy Equivalence: Study of relativity led to one of
the greatest inventions, i.e., E = mc2 where E is Energy, m
stands for mass and c for the velocity of light. Many
scientists observed that the object’s mass increases with the
velocity but never knew how to calculate it. This equation is
the answer to their problem, which explains that the
increased relativistic weight of the object is equal to the
kinetic energy divided by the square of the speed of light.
•
General Theory of Relativity
• General Relativity theory, developed by Einstein in 1907-
1915, states that being at rest in the gravitational field and
accelerating are identical physically. For example, an
observer can see the ball fall the same way on the rocket
 and on Earth. This is due to the rocket’s acceleration, which
equals 9.8 m/s2. This theory relates to Newton’s
gravitational theory and special relativity.
Some Consequences of General Relativity are :
• Gravitational Time Dilation: Gravity influences the passage
of time. Clocks in the deeper gravitational wells run slower
than in general gravitational levels.
• Light rays will bend in the gravitational field.
• The universe is expanding, and parts of it are moving away
from Earth faster than the speed of light.

V. Nuclear Physics
Nuclear physics is the field of physics that studies atomic nuclei and
their constituents and interactions, in addition to the study of other
forms of nuclear matter.
Nuclear physics should not be confused with atomic physics, which
studies the atom as a whole, including its electrons.
Discoveries in nuclear physics have led to applications in many fields.
This includes nuclear power, nuclear weapons, nuclear medicine and
magnetic resonance imaging, industrial and agricultural isotopes, ion
implantation in materials engineering, and radiocarbon dating in
geology and archaeology. Such applications are studied in the field of
nuclear engineering.
Particle physics evolved out of nuclear physics and the two fields are
typically taught in close association. Nuclear astrophysics, the
application of nuclear physics to astrophysics, is crucial in explaining the
inner workings of stars and the origin of the chemical elements.
The history of nuclear physics as a discipline distinct from atomic
physics, starts with the discovery of radioactivity by Henri Becquerel in
1896,[1] made while investigating phosphorescence in uranium salts.[2]
The discovery of the electron by J. J. Thomson[3] a year later was an
indication that the atom had internal structure. At the beginning of the
20th century the accepted model of the atom was J. J. Thomson's
"plum pudding" model in which the atom was a positively charged ball
with smaller negatively charged electrons embedded inside it.
In the years that followed, radioactivity was extensively investigated,
notably by Marie Curie, Pierre Curie, Ernest Rutherford and others. By
the turn of the century, physicists had also discovered three types of
radiation emanating from atoms, which they named alpha, beta, and
gamma radiation. Experiments by Otto Hahn in 1911 and by James
Chadwick in 1914 discovered that the beta decay spectrum was
continuous rather than discrete. That is, electrons were ejected from
the atom with a continuous range of energies, rather than the discrete
amounts of energy that were observed in gamma and alpha decays.
This was a problem for nuclear physics at the time, because it seemed
to indicate that energy was not conserved in these decays.
The 1903 Nobel Prize in Physics was awarded jointly to Becquerel, for
his discovery and to Marie and Pierre Curie for their subsequent
research into radioactivity. Rutherford was awarded the Nobel Prize in
Chemistry in 1908 for his "investigations into the disintegration of the
elements and the chemistry of radioactive substances".
In 1905, Albert Einstein formulated the idea of mass–energy
equivalence. While the work on radioactivity by Becquerel and Marie
Curie predates this, an explanation of the source of the energy of
radioactivity would have to wait for the discovery that the nucleus itself
was composed of smaller constituents, the nucleons.
Rutherford discovers the nucleus
James Chadwick discovers the neutron

VI. Quantum physics

Quantum physics is the study of matter and energy at the most
fundamental level. It aims to uncover the properties and behaviors of
the very building blocks of nature.
While many quantum experiments examine very small objects, such as
electrons and photons, quantum phenomena are all around us, acting
on every scale. However, we may not be able to detect them easily in
larger objects. This may give the wrong impression that quantum
phenomena are bizarre or otherworldly. In fact, quantum science closes
gaps in our knowledge of physics to give us a more complete picture of
our everyday lives.
The Origins of Quantum Physics
The field of quantum physics arose in the late 1800s and early 1900s
from a series of experimental observations of atoms that didn’t make
intuitive sense in the context of classical physics. Among the basic
discoveries was the realization that matter and energy can be thought
of as discrete packets, or quanta, that have a minimum value
associated with them. For example, light of a fixed frequency will
deliver energy in quanta called “photons.” Each photon at this
frequency will have the same amount of energy, and this energy can’t
be broken down into smaller units. In fact, the word “quantum” has
Latin roots and means “how much.”
Knowledge of quantum principles transformed our conceptualization of
the atom, which consists of a nucleus surrounded by electrons. Early
models depicted electrons as particles that orbited the nucleus, much
like the way satellites orbit Earth. Modern quantum physics instead
understands electrons as being distributed within orbitals,
mathematical descriptions that represent the probability of the
electrons’ existence in more than one location within a given range at
any given time. Electrons can jump from one orbital to another as they
gain or lose energy, but they cannot be found between orbitals.
Other central concepts helped to establish the foundations of quantum
physics:

Wave-particle duality: This principle dates back to the earliest days of

quantum science. It describes the outcomes of experiments that
showed that light and matter had the properties of particles or waves,
depending on how they were measured. Today, we understand that
these different forms of energy are actually neither particle nor wave.
They are distinct quantum objects that we cannot easily conceptualize.
Superposition: This is a term used to describe an object as a
combination of multiple possible states at the same time. A superposed
object is analogous to a ripple on the surface of a pond that is a
combination of two waves overlapping. In a mathematical sense, an
object in superposition can be represented by an equation that has
more than one solution or outcome.
Uncertainty principle: This is a mathematical concept that represents a
trade-off between complementary points of view. In physics, this
means that two properties of an object, such as its position and
velocity, cannot both be precisely known at the same time. If we
precisely measure the position of an electron, for example, we will be
limited in how precisely we can know its speed.
Entanglement: This is a phenomenon that occurs when two or more
objects are connected in such a way that they can be thought of as a
single system, even if they are very far apart. The state of one object in
that system can’t be fully described without information on the state of
the other object. Likewise, learning information about one object
automatically tells you something about the other and vice versa.

Reference(s)
I. Dalton’s atomic theory. (2016, June 22). Chemistry
LibreTexts; Libretexts.
https://chem.libretexts.org/Bookshelves/Introduct
ory_Chemistry/Introductory_Chemistry_(CK-12)/
04%3A_Atomic_Structure/
4.06%3A_Dalton’s_Atomic_Theory
II. Modern physics. (1955). Journal of the Franklin
Institute, 260(5), 442.
https://doi.org/10.1016/0016-0032(55)90172-1