NUCLEAR CHEMISTRY - Radioactivity & Radiation - Alpha, Beta, Gamma

Summary

In 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

00:00

🔬 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.

05:03

🌐 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.

10:05

💥 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.

Keywords

💡Nucleus

The nucleus is the central part of an atom, containing protons and neutrons. It is the focus of the video's discussion on atomic stability. The video explains that an unstable nucleus, due to an unfavorable combination of protons and neutrons, can lead to radioactivity. For example, the script mentions that isotopes of chlorine with different numbers of neutrons can result in an unstable nucleus.

💡Isotopes

Isotopes are variants of a chemical element that have the same number of protons but different numbers of neutrons. The video uses isotopes to illustrate how changes in the number of neutrons can affect the stability of a nucleus. It's highlighted that isotopes of chlorine with varying neutron counts can lead to differences in mass and, potentially, instability.

💡Radioactivity

Radioactivity refers to the spontaneous emission of particles or energy from an unstable atomic nucleus. The video script explains that radioactivity is a sign of an unstable nucleus and is a process that leads to the release of radiation. It is a key concept in nuclear chemistry and is tied to the natural decay process of certain elements.

💡Radiation

Radiation, in the context of the video, is the emission from an unstable nucleus, which can be in the form of particles (alpha or beta) or high-energy waves (gamma). The video script describes how radiation is a byproduct of an unstable nucleus trying to achieve stability, with examples including alpha, beta, and gamma radiation.

💡Alpha Particle

Alpha particles are helium nuclei consisting of two protons and two neutrons. The video script explains that alpha particle decay occurs when an unstable nucleus emits an alpha particle, effectively reducing its mass number by four and its atomic number by two. This process is used as an example to illustrate how an atom can become more stable by losing mass.

💡Beta Particle

Beta particles are high-energy electrons that are emitted when a neutron in an unstable nucleus transforms into a proton. The video script describes beta particle decay as a process where the nucleus reduces its neutron count and increases its proton count, thus moving one step up the periodic table.

💡Gamma Radiation

Gamma radiation is a form of high-energy electromagnetic radiation emitted from an unstable nucleus as it transitions to a lower energy state. Unlike alpha and beta decay, gamma radiation does not involve a change in the atomic number or mass number. The video script uses the analogy of opening a soda bottle to release pressure, similar to how an atom releases gamma radiation to become more stable.

💡Nuclear Strong Force

The nuclear strong force is the force that holds the protons and neutrons together in an atomic nucleus. The video script mentions that this force operates over a short distance and is crucial for maintaining the nucleus's integrity. An imbalance in the number of protons and neutrons can overcome this force, leading to an unstable nucleus.

💡Stability

Stability, in the context of the video, refers to the condition of an atom or nucleus where it is not prone to change or decay. The video script explains that stability is determined by the ratio of protons to neutrons in the nucleus. An unstable nucleus will undergo nuclear changes to achieve a more stable configuration.

💡Proton

Protons are subatomic particles with a positive electric charge found in the nucleus of an atom. The video script discusses how the number of protons determines the element, and an imbalance in the number of protons can lead to an unstable nucleus. The script also mentions that too many protons can cause repulsion within the nucleus.

💡Neutron

Neutrons are subatomic particles with no net electric charge that are found in the nucleus of an atom. The video script explains that while neutrons do not affect the electrical stability of the nucleus, an excess can still lead to instability. Neutrons play a role in determining the mass of an isotope and its stability.

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