NUCLEAR CHEMISTRY - Radioactivity & Radiation - Alpha, Beta, Gamma
Summary
TLDRIn this educational video, Mr. Post explores the concept of nuclear instability, explaining how an unfavorable ratio of protons to neutrons can destabilize an atom's nucleus. He introduces the nuclear strong force that normally holds the nucleus together but fails when the atom is unstable. The video delves into radioactivity, defining it as an unstable nucleus's spontaneous change and contrasting it with radiation, which is the actual emission of particles or energy. Mr. Post covers the three main types of nuclear radiation: alpha, beta, and gamma, each with its unique characteristics and effects on the nucleus's stability. The goal of radiation emission is to achieve a more stable nucleus.
Takeaways
- 🔬 Isotopes are different forms of the same element, varying in the number of neutrons.
- 🌐 The nuclear strong force is a mysterious force that holds the nucleus together despite the repulsion of protons.
- ⚠️ An unstable nucleus has an unfavorable ratio of protons to neutrons, leading to nuclear changes.
- 💥 The maximum number of protons naturally found in a nucleus is 92, as seen in uranium.
- 📉 Radioactivity is a sign of an unstable nucleus, which may undergo spontaneous changes.
- ➡️ Radiation is emitted from unstable nuclei and can be in the form of particles (alpha, beta) or energy (gamma).
- 🚀 Alpha particle decay involves the release of two protons and two neutrons, reducing the atomic number by two.
- 🔄 Beta particle decay occurs when a neutron converts into a proton and emits an electron.
- 🔆 Gamma radiation is high-energy radiation emitted from an unstable nucleus to increase stability without changing the element.
- 🔬 Nuclear chemistry focuses on changes within the nucleus, which contains protons and neutrons.
Q & A
What is an isotope?
-An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons in its nucleus, resulting in different atomic masses.
Why might a nucleus be unstable?
-A nucleus might be unstable due to an unfavorable combination of protons and neutrons, leading to too many protons pushing each other apart or too many neutrons causing instability.
What is the nuclear strong force?
-The nuclear strong force is the force that holds the nucleus of an atom together, operating over a small distance such as within the nucleus.
What is the maximum number of protons a naturally occurring nucleus can have?
-The maximum number of protons a naturally occurring nucleus can have is 92, as seen in uranium.
What is meant by the term 'radioactivity'?
-Radioactivity refers to the spontaneous process by which an unstable nucleus loses energy by emitting radiation, such as alpha, beta, or gamma radiation.
How does an atom become more stable through radiation?
-An atom becomes more stable by emitting radiation, which can be in the form of particles (alpha or beta) or energy (gamma), thus reducing the imbalance of protons and neutrons in the nucleus.
What is alpha particle decay?
-Alpha particle decay is a type of radioactive decay in which an unstable nucleus emits an alpha particle, which consists of two protons and two neutrons, effectively decreasing the atomic number by two and the mass number by four.
What is beta particle decay?
-Beta particle decay is a process where a neutron in an unstable nucleus is converted into a proton and an electron (beta particle), which is then emitted from the nucleus, increasing the atomic number by one.
How is gamma radiation different from alpha and beta radiation?
-Gamma radiation is not a particle but a high-energy electromagnetic wave emitted from an unstable nucleus. It does not change the atomic number or mass number of the nucleus, unlike alpha and beta radiation.
What is the role of the neutron in beta particle decay?
-In beta particle decay, a neutron in the nucleus is converted into a proton and an electron (beta particle). This process helps the nucleus achieve a more stable configuration by reducing the number of neutrons.
Why does the nuclear strong force fail in certain nuclei?
-The nuclear strong force fails in certain nuclei when the repulsive force between protons becomes too strong due to too many protons, or when the balance of protons to neutrons is unfavorable, leading to an unstable nucleus.
Outlines
🔬 Understanding Atomic Instability
This paragraph discusses the concept of atomic instability, focusing on why a nucleus might be unstable. It introduces the terms 'radioactivity' and 'radiation' and explains the three common forms of nuclear radiation: alpha, beta, and gamma. The paragraph begins by explaining isotopes, which are different forms of the same element with varying numbers of neutrons. It then delves into the role of the nuclear strong force, which holds the nucleus together despite the repulsion between positively charged protons. The key takeaway is that an unstable nucleus is due to an unfavorable ratio of protons to neutrons, which can lead to spontaneous changes or decay.
🌐 The Nature of Radiation
The second paragraph delves into what radiation actually is, distinguishing between the adjective 'radioactive' which describes the condition of an atom, and 'radiation' which is the actual emission from an unstable nucleus. It explains that radiation can take the form of particles such as alpha and beta particles, or energy in the form of gamma radiation. The paragraph emphasizes that the emission of radiation is a means for an atom to achieve greater stability. It provides examples of alpha and beta decay, explaining how alpha decay involves the emission of a helium nucleus (two protons and two neutrons), and beta decay involves a neutron converting into a proton and emitting an electron.
💥 Exploring Types of Radiation
The final paragraph of the script focuses on the different types of radiation in detail. It explains gamma radiation as a form of high-energy wave emission from an unstable nucleus, which does not result in a change of element but helps the nucleus achieve stability. The paragraph summarizes the lesson by reiterating that nuclear chemistry deals with changes in the nucleus, caused by an unstable nucleus with too many protons or neutrons. It also previews the next lesson, which will discuss the nuclear changes associated with alpha, beta, and gamma radiation in more depth.
Mindmap
Keywords
💡Nucleus
💡Isotopes
💡Radioactivity
💡Radiation
💡Alpha Particle
💡Beta Particle
💡Gamma Radiation
💡Nuclear Strong Force
💡Stability
💡Proton
💡Neutron
Highlights
Understanding why a nucleus may be unstable is the main goal of the video.
Isotopes are different forms of the same element with varying numbers of neutrons.
An unstable isotope of chlorine is used as an example to explain instability.
The nuclear strong force is the force that holds the nucleus together.
Too many protons or neutrons can lead to an unstable nucleus.
Stability of an atom is based on the ratio of protons to neutrons.
Uranium with 92 protons is the maximum size a nucleus can contain naturally.
Unstable atoms undergo nuclear changes.
Radioactivity is a term used to describe an unstable nucleus.
Radiation is given off from an unstable nucleus and can be in the form of particles or energy.
Alpha particles are the largest particles of radiation and consist of two protons and two neutrons.
Beta particles are smaller than alpha particles and are essentially electrons.
Gamma radiation is high-energy radiation released from an unstable nucleus.
Alpha particle decay involves the release of four particles from the nucleus.
Beta particle decay occurs when a neutron changes into a proton and releases an electron.
Gamma radiation is released to make the atom more stable.
Nuclear chemistry deals with changes in the nucleus due to instability.
The video concludes with a summary tying together the concepts of nuclear chemistry, radioactivity, and radiation.
Transcripts
hey guys this is Mr post and on today's
video the goal is to understand why a
nucleus may be unstable to understand
the terms radioactivity and radiation
and also to understand the three common
forms of nuclear radiation known as
alpha beta and gamma radiation a little
while back we looked at Isotopes
Isotopes are the same element but just
different forms of the same element and
one thing you're going to see is that
they vary in the number of neutrons so
the 17 refers to the number of proton
and nucleus 17 protons so they all are
the same element they're all chlorine
but they come in different masses
meaning they have a different nucleus or
slightly heavier nucleus this in this
case it has 35 particles in nucleus 36
particles in nucleus and 37 particles of
nucleus but this dude right here this
isotope of chlorine is unstable and the
goal of the first part of the lesson is
to focus on what makes that unstable now
there is this crazy mysterious force
that we don't know too much about it's
called the nuclear strong force it is
the force that holds the nucleus of an
atom together all right check this out
guys check this out let's just call the
yellows protons any yellow has a
positive charge
and if we know anything about like mag
magnets maybe you used them before
you'll notice that when you have the
same ends of a magnet next to each other
they actually do this they push each
other apart now just picture that all
positives should push each other apart
and that's what's going on here these
two guys should push each other apart
these two guys should push each other
apart and so really what you should have
is that the nucleus should kind of fall
apart or blow apart but it doesn't and
we've come to find out that there this
weird mysterious force that operates
over a small distance such as the
nucleus of an atom and it holds the
nucleus
together when your atom is unstable and
is going to be unstable because you
might have too many protons that are
pushing each other apart and also too
many neutrons now just because the
neutrons don't have a charge doesn't
mean they can't cause a nucleus to
become unstable all right they have no
charge but still if you have too many of
them it might not lead to a
favorable combination of protons and
neutrons in the nucleus we use this term
stability stability means the atom is
going to be around like forever it is
not going to change an unstable atom
will undergo what we know as nuclear
changes and ability is based on the
ratio of protons to neutrons and that's
why I say too many protons is not good
and likewise too many neutrons is not
good they're going to end up forming a
ratio that is either favorable or
unfavorable when you have an unstable
atom what you're going to find out is
that the nuclear strong force will Now
fail that is right it will break down it
can no longer do its job and hold the
nucleus together and what you're going
to have is a nuclear change that takes
place in nature what you're going to see
is that 92 protons is the maximum size a
nucleus can contain naturally so in
nature 92 protons is uranium and uranium
has might have a mass number of
something around 238 particles in
nucleus that is a massive nucleus think
about this there's 92 positive charges
and I've already told you that they
repel each other on top of that you're
going to have a whole ton of neutrons
238 particles total protons neutrons in
your nucleus the nuclear strong force
cannot hold that nucleus together that
well and so 92 is the maximum number of
protons you can find in nature we do
have atoms bigger than 92 but those are
manmade synthetic
atoms so once again guys if I could sum
up why is a nucleus unstable I'd say
it's unstable really because there's a
bad combination an unfavorable
combination of protons and neutrons this
right here is a good combination this
right here is an appropriate or stable
combination of protons and neutrons and
36 as your mass number which gives you
19 neutrons and 17 protons that is not a
favorable condition for nucleus and the
nuclear strong force cannot hold it the
second part of the lesson is going to
focus on radioactivity and when I say an
atom is radioactive what I'm really
saying is that the nucleus is
unstable it might
fall apart a change might occur in it at
any point in time it said to be a
spontaneous change so we looking at a
word radioactive radioactive is nothing
more than an adjective that describes
the atom that's all it is and instead of
saying radioactive I could say unstable
so when you hear something as
radioactive it is simply described the
condition of the atom it is an adjective
used to describe the condition of the
atom the condition of the
nucleus so something that is Radio
active is going to give off radiation a
very similar word but whereas
radioactive describes the atom radiation
is an actual
thing so radiation is going to be a
couple things I have in this picture
here radiation can either be a a
particle such as that particle right
there it could be a smaller particle
such as this and radiation as far as
nuclear radiation goes could come in the
form of
energy generally what ends up happening
is that when you give off off particles
you form a new nucleus because now parts
of your nucleus have left so when I say
particles what I'm really saying is part
of something part of the nucleus is
going to be released from the
atom so in summary radiation is given
off from an unstable nucleus and
radiation is nothing more than either
energy such as gamma
radiation or it may be particles such as
has alpha particles and beta
particles one of the goals of an atom
has of giving off radiation is that it's
going to make it a little bit more
stable and that's the condition it wants
to get to right now this is a
nonfavorable condition for my nucleus
and the nucleus is going to have its
goal of getting more stable and it will
become more stable by giving off
particles such as alpha particles and
beta particles and also giving off
energy so when I look at the types of
radiation for us the common ones are
going to be alpha particles they're the
largest particles as far as radiation
goes we're going to have beta particles
they're going to be smaller particles
very very small but they're going to be
particles that are given off out of the
nucleus and not a particle but simply
high energy radiation would be gamma
radiation so these are the big three
we're going to discuss and we're going
to take one slide a piece for each one
of them
alpha particles are also known as alpha
particle Decay Decay means the nucleus
is decaying or changing or breaking
apart so we could be called alpha
particle Decay or also alpha particle
radiation as you see this nucleus is
going to undergo a change in the picture
I've drawn here I'm trying to express
this in a picture is that the nucleus is
going to fire off four particles now
what you want you to see here is that if
this was to happen to chlorine I'm not
saying it does happen to chlorine this
is just a good example here chlorine has
36 particles in nucleus and if it was to
undergo alpha particle Decay it would
release four of the 36 particles from
this nucleus and those particles would
go off so it is when a nucleus releases
two protons and two
neutrons let's call the Yellow Ones
protons and I'm put a zero here a zero
for my neutrons so my new leftover
nucleus over here is going to be four
four particles smaller than chlorine as
36 my new nucleus is going to have four
particles smaller two protons two
neutrons so check out what I'm going to
do I'm simply going to do 36 is my
previous mass number of the particles in
my nucleus there's 36 particles there
before I'm going to subtract out my four
and now I'm down to 32 particles in my
nucleus so my new mass number now that
these guys are gone is
32 my new atomic number the atomic
number is the number of protons and as
you see we just lost two protons I'm
down to element number 15 on the
periodic
table now I don't have a periodic table
in front of me so you're have to forgive
me if I get this wrong but I do believe
that is the element phosphorus okay so I
don't have a periodic in front of me
recording this video but I think it's
phosphorus the way scientists will
Express an alpha particle because we
want to save time save our words we're
going to use a symbol 4 over2 H because
you have to realize this that this is
actually part of a nucleus it's actually
almost like a new nucleus that's been
formed over here the new nucleus has
four particles that's the mass number
well the yellow ones are set were
protons there's two of them anytime I
have two protons that element is going
to be identified as being helium and it
is fired without electrons it is
released fired away without electrons
giving it a two positive charge because
I have two protons and in this case I
have zero as my electrons giving me a
two positive charge so that's alpha
particle Decay when the nucleus releases
four particles two protons and two
neutrons and that is the combination
that will happen in the next thing we're
going to look at is beta particle Decay
so my nucleus has too many protons too
many neutrons it's undergoing these
changes in beta particle Decay what
you're looking at is this little
particle that's going to be released
from the nucleus the little particle is
actually an electron you got it an
electron is going to be released from
the nucleus of an atom beta particle
Decay is when a neutron changes into a
proton and I know you're saying holy
smokes how can this possibly happen it
does all right we've studied these atoms
for a long time now and we have seen a
neutron can change into a proton you
know it's not too far-fetched to believe
that they both have the same mass one
atomic mass unit and actually
technically the neutron is just a hair
heavier than the proton so a neutron is
going to change into a proton but in the
process it's going to create an electron
that electron is going to be fired out
or released into the atmosphere into the
environment
this dude right here this electron he is
the beta particle so I say I undergo
beta particle Decay beta particle
radiation I'm really saying is that yes
electron was created an electron was
fired off but it was fired off because a
neutron changed into a proton so why do
these things happen well let's take a
step back all right let's go to this
previous slide here alpha particles will
be released because there are too many
protons and neutrons in nucleus and the
nucleus is trying to get r of both the
protons and the neutrons on the current
one we're looking at here this will
occur when I have too many of these guys
too many neutrons and a neutron then
changes into a proton although not
expressed in this lesson in a different
lesson I might Express a proton can
change into a neutron so these nuclear
changes do take place but in this case
an electron is produced and that is my
radiation the particle given off from my
un
nucleus we express this as 01 e once
again there's no mass in an electron
therefore you have no mass number
instead of a proton we have a negative
one down here and E minus is my
symbol the last particle we'll be
looking at today is gamma radiation I
shouldn't say the last particle I should
say the
last the last form of radiation that
we're looking at today is not a particle
okay it is is what we call high energy
that is released from an unstable
nucleus now yes I use the lightning bolt
over here but really what is it it is a
wave of energy that is given off from an
unstable nucleus now in this form of
radiation it's different there is no
Mass associated with energy there's no
Mass associated with it so the element
doesn't change I don't change into a
brand new element I say the same element
I've just released them energy and it's
really expressed as zero as the mass
number Z is the atomic number and we're
actually really going to express it as
this this is the Greek letter for gamma
so I've written the word over here 0
gamma to give you an idea of what we're
looking at here no mass and no charge
honestly I kind of think of this as like
you know you open a coke bottle and you
release the cap a little bit and some
air comes out that's what gamma
radiation kind of is some steam is being
let off of an unstable nucleus why the
whole goal is to make it more stable and
by releasing a little bit of gamma
radiation my atom becomes more
stable so let's go into a summary here
okay if I'm going to like tie up the
whole entire lesson at this point I
could easily do so on this slide here
nuclear chemistry deals with changes in
the nucleus the nucleus contains protons
and
neutrons radioactivity is caused by an
unstable nucleus and too many protons
and too many neutrons may cause the
nucleus to become unstable and break
apart
radioactivity produces
radiation and this is a good way to tie
up and sum up this portion of the lesson
there will be another lesson following
this a different lesson and it's going
to be talking about alpha particles beta
particles and gamma radiation but we'll
discuss the nuclear changes that take
place I'd encourage you to tune into
that video all right guys thanks a lot
for watching have a great day
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