IGCSE Physics (2023-2025) - C22/25: The Nuclear Atom
Summary
TLDRThis IGCSE physics video explores nuclear physics, focusing on the atom's nucleus. Initially, the Plum Pudding model was debunked by Rutherford's experiment, leading to the Solar System model. The video explains the nucleus as a dense concentration of protons and neutrons, called nucleons. It covers atomic structure, isotopes, and nuclear reactions like fission and fusion, highlighting mass-energy conversion through Einstein's E=mc² formula. The video promises to delve into radioactive particles in the next installment.
Takeaways
- 🔬 The video discusses the module of IGCSE physics known as Nuclear Physics, which focuses on the properties of the atomic nucleus and the reactions that occur within it.
- 🍮 The Plum Pudding model, an early atomic model, was disproved by Ernest Rutherford's gold foil experiment, which demonstrated that the atom has a small, dense, positively charged nucleus.
- 🔋 Alpha particles, consisting of two protons and two neutrons, were used in Rutherford's experiment, and their deflection indicated the presence of a concentrated positive charge within the atom.
- 🌐 The Solar System model of the atom emerged from Rutherford's findings, with a central nucleus containing protons and neutrons, and electrons orbiting around it.
- 🚩 Protons and neutrons are collectively known as nucleons and are located in the nucleus, while electrons orbit the nucleus.
- ⚖️ The relative mass of electrons is much less than that of protons and neutrons, which is why they have a negligible impact on the atom's overall mass.
- 📊 The number of protons determines the element's identity on the periodic table, and the atomic number is the sum of protons and neutrons.
- 🔄 Isotopes are variants of an element that have the same number of protons but different numbers of neutrons, resulting in different masses.
- 💥 Nuclear fission is a reaction where a heavy nucleus, like uranium, splits into smaller nuclei after absorbing a neutron, releasing energy and more neutrons.
- 🌟 Nuclear fusion is a process where light nuclei, such as hydrogen, combine to form a heavier nucleus, like helium, releasing a large amount of energy.
- ⚡ The mass defect observed in nuclear reactions is explained by Einstein's famous equation, E=mc^2, where lost mass is converted into energy.
Q & A
What is the main focus of Nuclear Physics in the context of IGCSE physics?
-Nuclear Physics in IGCSE physics focuses on the properties of the nucleus of an atom and the reactions that occur within it.
What was the Plum Pudding model and why was it disproven?
-The Plum Pudding model was an early atomic model that suggested the atom consisted of a positive 'pudding' with protons and electrons scattered within it. It was disproven by Ernest Rutherford's experiment, which demonstrated that the atom has a small, dense, positively charged nucleus.
What did Rutherford's experiment involve and what was the key observation?
-Rutherford's experiment involved firing alpha particles at a thin piece of gold foil. The key observation was that while most alpha particles passed through, a few were deflected back, indicating a concentrated positive charge within the atom, which led to the discovery of the nucleus.
What is the Solar System model of the atom and how does it differ from the Plum Pudding model?
-The Solar System model of the atom, also known as the Rutherford model, places a small, dense, positively charged nucleus at the center of the atom with electrons orbiting around it, similar to planets orbiting the sun. This differs from the Plum Pudding model, which suggested a uniform distribution of positive charge with electrons scattered throughout.
What are nucleons and what are their components?
-Nucleons are the particles found in the nucleus of an atom, and they consist of protons and neutrons.
How does the number of protons in an atom determine its position in the periodic table?
-The number of protons in an atom, also known as the atomic number, determines its position in the periodic table because it defines the element's identity. Elements are arranged in ascending order of atomic number.
What is the relationship between the nuclear number, proton number, and neutron number in an atom?
-The nuclear number (also known as the mass number) is the total number of protons and neutrons in an atom. The proton number is the count of protons, and the neutron number can be found by subtracting the proton number from the nuclear number.
What are Isotopes and how do they differ from each other?
-Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This results in different atomic masses but the same chemical properties.
What is nuclear fission and how does it occur?
-Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts, usually when struck by a neutron. This process releases energy and additional neutrons, which can lead to a chain reaction.
What is nuclear fusion and how does it differ from nuclear fission?
-Nuclear fusion is a nuclear reaction where two light atomic nuclei combine to form a heavier nucleus, releasing a large amount of energy. It differs from nuclear fission in that fusion involves the combination of nuclei rather than their splitting.
How is the mass deficit in nuclear reactions accounted for according to Einstein's famous equation?
-According to Einstein's equation, E=mc^2, the mass deficit in nuclear reactions is converted into energy. The lost mass (m) multiplied by the speed of light (c) squared gives the energy (E) released during the reaction.
Outlines
🔬 Introduction to Nuclear Physics
This segment introduces the topic of Nuclear Physics within the IGCSE physics curriculum. It explains the historical Plum Pudding model of the atom, which was later disproved by Ernest Rutherford's gold foil experiment. The experiment involved firing alpha particles at a thin sheet of gold and observing their deflection, which led to the discovery of the nucleus. The nucleus, a small, dense region at the center of an atom, contains all the positive charge and most of the mass of the atom, composed of protons and neutrons. The video also explains the Solar System model of the atom, where electrons orbit the nucleus, and provides a recap of the structure of an atom, including the roles of protons, neutrons, and electrons.
🧬 Atomic Structure and Isotopes
This section delves into the atomic structure, focusing on the nucleus and its components—protons and neutrons, collectively known as nucleons. The video explains the concept of isotopes, which are variants of an element with the same number of protons but different numbers of neutrons, resulting in different atomic masses. The nuclear number and proton number are introduced as tools to determine the number of neutrons in an atom. The video uses the example of calcium to illustrate this concept. It also touches on the properties of the nucleus, including its charge and mass, and how these relate to the number of protons and neutrons. The difference between nuclear fission and fusion is briefly introduced, setting the stage for further exploration in subsequent videos.
⚛️ Nuclear Reactions and Einstein's E=mc²
The final segment of the video discusses nuclear reactions, specifically nuclear fission and fusion, and their energy release. It explains the process of nuclear fission, where a uranium atom absorbs a neutron and splits into smaller elements, releasing energy and additional neutrons. This can lead to a chain reaction. The video also covers nuclear fusion, where two light nuclei combine to form a heavier nucleus, releasing energy. The famous equation E=mc² by Albert Einstein is introduced to explain the conversion of mass into energy during these reactions. The video concludes by summarizing the disproval of the Plum Pudding model, the study of atomic properties, and a teaser for the next video, which will explore radioactive particles.
Mindmap
Keywords
💡Nuclear Physics
💡Nucleus
💡Plum Pudding Model
💡Rutherford Experiment
💡Alpha Particles
💡Nuclear Fission
💡Nuclear Fusion
💡Isotopes
💡Einstein's E=mc²
💡Subatomic Particles
Highlights
Introduction to the IGCSE physics module on Nuclear Physics.
Definition of the nucleus and its significance in atomic structure.
Historical context: The Plum Pudding model and its disproof.
Ernest Rutherford's experiment that led to the disproof of the Plum Pudding model.
Description of the Solar System model of the atom.
Explanation of how Rutherford's experiment disproved the Plum Pudding model.
The discovery of the nucleus as a concentrated positive charge within the atom.
Visual representation of Rutherford's findings on atomic structure.
Recap of the atom's structure according to the Solar System model.
Definition and properties of subatomic particles: protons, neutrons, and electrons.
Explanation of how the number of protons determines an element's identity.
Visualizing elements using the nuclear number and proton number.
Introduction to Isotopes and their significance in nuclear physics.
The concept that Isotopes share the same chemical properties but differ in mass.
Explanation of nuclear fission and its role in releasing energy.
The process of balancing nuclear reactions by conserving the number of nucleons.
The concept of chain reactions in nuclear fission.
Introduction to nuclear fusion and its energy release.
Einstein's famous equation, E=mc², and its application in nuclear reactions.
Summary of the video's key points on nuclear physics and a preview of the next topic: radioactive particles.
Transcripts
hello everyone in this video we're going
to look into another module of IGCSE
physics called The Nuclear Physics so
the word nucleus stems from the word
nucleus which means that this branch of
physics study what is the properties of
the nucleus of an atom and what are the
reactions that comes out from it so
initially scientists thought that
nucleus follows this model called The
Plum Pudding model so it is a disproof
model of the atom which imagine it to be
consists of a positive pudding like the
protons here and the electrons on the
other side so it's like a pluting and
how it is disproof is from this
experiment carried out by Ernest
ratafort so what they figure out is that
hey the atom should look like that so
this is also known as The Solar System
model of the atom and the experiment
that They carried out is this so what
Rutherford and the team does is that
they fire the alpha particles so alpha
particles is a particle of made up of
two protons and two neutrons
and at a very thin piece of goeth go for
so if the atom really follows the plum
pudding water right so it they should
they predict that the alpha particle
should pass straight through the goal
and what they found out is that most of
the particle pass straight through the
void as predicted and some of them they
deflected scarcely and a few of these
alpha particles they actually bounce
back towards the source of radiation
so what this experiment shows according
to Rutherford is that because alpha
particles are positively charged they
have two protons and if they are
repelled back from the Gopher is it must
be another positive charge remember
chapter 17 when we talk about electrical
repulsion so there must be another
positive charge
but what the experiments show is that
only a few are repelled and it shows
that the positive charge of the gold
atoms was concentrate in a tiny space
within the atom
and if not that would be a law of
deflection but then they found out that
only a few bounce back it shows that
protons in an atom is gathered around a
particular space
and the tiny curve concentrated positive
charge at the heart of every atom is
what we call today the nucleus the
nucleus of an atom and to show you an
image form of what Waterford explained
this is it
so they figure out that new there's
actually a tiny spot in an atom that
consists of all the positive charge
which is the nucleus that explains why
only a few of the alpha particle is
reflected directly back at the source
so in this image from this is what it
meant and again here's a recap on the
structure of an atom
um here we have nucleus in the middle
the Solar System model as what it's
shown by rather Fort they consist of
proton and also Neutron and we're now
looking to since we now have proved that
the structure of an atom follow the
Solar System model so we will
investigate it further so in the center
of the atom is the nucleus they have
proton and neutron
and the electrons is the one that is
surrounding the atom
so um by the way if you put together
proton and neutron they are known as
nucleons
so this table summarized the information
and masses and charges of the three
subatomic particles protonutrient
electrons so both protons and neutrons
that's in the nucleus whereas electrons
is orbiting the nucleus and as we
mentioned in chapter 17
proton has a charge of 1.6 times 10 to
the power of negative 19 column so its
relative charge is one as compared to
Neutron
and the mass of it is this amount and
you can see that new electrons here they
are heavier I mean they are less lighter
than proton and neutron so that's why
when you calculate relative mass so this
is the proportion of mass that electron
has that's compared to proton so that
suggests some properties of the three
subatomic particles
and if we look into atom what determines
the particular element in the periodic
table is the number of protons so if you
take chemistry you should be able to
notice and they are arranged in
ascending order in others accordance to
how many protons the atom has
and this is a way for us to visualize an
element so this is the helium element
and their first number notations here
first number stands for nuclear number
which is the amount of proton
plus the amount of nucleons Neutron
so two here stand for a proton number
they're not protons so in other words by
using this nuclear number and proton
number we can figure out how many
neutrons by using the nuclear number
minus the proton number so that's just a
very simple formula
and what can you deduce from whose the
atom whose nucleus can be represented by
this so this is a calcium we know that
they have 14 nucleon
and then six protons
so this shows us that there are six
protons here
oops let me use another color six
protons and because they have 14
nucleons mean that if you want to find
the number of neutrons you have to use
14 minus six therefore you get eight
Neutron
and also six electrons because we're
considering that this element is
um neutral meaning they have the same
amount of electrons and protons
so protons 14 and cloud and eight all
right so that's about it and when we
talk about elements some elements they
have something called the Isotopes
Isotopes means that they these elements
have the same number of protons making
them the same element but then
um they have sometimes different neutron
number that means they are heavier in
terms of their nucleus so for instance
helium-4 and helium-3 they have the same
number of protons but helium 4 will have
more neutrons so in other words they
have four nucleons so that's why name
nuclear force comes from again two three
five and two three eight uranium is the
same they have same proton number
different neutron number so these
Isotopes they have same chemical
properties because they have same number
of protons but then those with greater
number of neutrons is going to be
heavier
so the charge on the nucleus is equal to
the number of protons
so it has a relative charge of plus one
and the math of the nucleus is relative
equal to the mass of the nucleon as both
protons and neutron neutron has a
relative mass of one so go back to our
example just now if I have a uranium 235
it has a charge of plus 235 because
it has 92 plus 92 charge because it has
92 protons
and then for Uranium the mass will be
235 because that's the amount of nucleon
that it has
so when it comes to so now we have
studied the structure of an atom so
let's look into some of the reactions
that can occur in the nucleus of an
element first one is nuclear fission we
have already learned this in chapter
seven
and it happens when in uranium get hits
by a neutron
so the additional neutrons here will
make the uranium unstable
and therefore it will undergo precise
called nuclear fission
to two different elements here
and then with three again three neutrons
most importantly is the energy that they
release so that's um the formulas the
equation of nuclear fission you can see
that uranium gets hit by a neutron it
becomes this element plus this element
plus two Neutron plus some energy one
thing to note here is do you look at the
amount of protons before and sorry
nucleon before and after the equation
you'll find out that if you sum this up
you'll get 236 and after the equation
you will get the same number
also
236 so the number of protons and
neutrons before and after nuclear
reaction is going to be the same that's
also how you can balance it
great so um they said also lead to chain
reaction because all these elements here
they could be hit by another element
that leads to more reaction to happen
and that's what happened in nuclear
fission and as for nuclear fusion it's a
lot simple it's when two hydrogen
elements like different hydrogen
elements they combine together to form
helium plus a neutron plus a lot of
energy
all right so what scientists found out
is that for both nuclear fission and
nuclear fusion
the total mass of the particles here
particle Mass
before a fission or fusion reaction is
slightly more than after Direction
meaning the mass of this
math A1 and the mass of this here Mass 1
is greater than MS2 but if you think
about it where does the loss Mass go
like where's the all this Mass we
converted to and that leads us to the
famous Einstein formula called e equal
to MC square m stands for the mass that
is lost during the equation
and then C stands for the speed of light
then you power by two
and if you use the mass loss multiplied
by the speed of light Square you will
get the energy release which can be
super big
um so imagine that 1 kg is lost
multiplied by 3 times 10 to the power of
8 power of two that is a huge amount of
energy so that that is just a basic
summary of what the equation equal to MC
squared stands for so in this video we
show how the plant putting model is
first disproved by ratified experiment
then we also study
um the different properties of proton
electrons and neutron so that's it for
this chapter in the next video we'll
look into how this nuclear reaction will
release something called radioactive
particles and I'll see in the next video
thank you so much for watching
Ver Más Videos Relacionados
Modelos atómicos (Goldstein, Becquerel, Curie, Rutherford) - Química Desde Cero
GCSE Chemistry Revision "The Nuclear Model"
GCSE Physics Revision "Alpha-Scattering and the Nuclear Model"
GCSE Chemistry - History of the Model of the Atom #7
Rutherford's Gold Foil Experiment - Quick and Simple!
Discovery of the Nucleus: Rutherford's Gold Foil Experiment
5.0 / 5 (0 votes)