Nuclear Chemistry: Crash Course Chemistry #38

In this episode, Hank welcomes you to the new age, to the new age, welcome to the new age. Here he'll talk about transmutation among elements, isotopes, calculating half-life, radioactive decay, and spontaneous fission.

Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!

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Table of Contents

Radioactivity
Transmutation Among Elements and Isotopes
Calculating Half-Life
Radioactive Decay
Spontaneous Fission
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[crashcourse]

Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App! 

[TobyKidMajor]

All hail Crash Course. Please don't stop making videos at least until I'm out of high school.

[basseenergie]

Nuclear physicist here, two quibbles with your video. First a small one : at 6:21 you say that beta decay has "higher energy" that alpha decay -- It hasn't. It does have higher range, or ability to penetrate matter, which is due to the electron being 8000 times lighter, and faster than an alpha for roughly the same energy. Second: GAMMA RADIATION IS NOT CAUSED BY ELECTRONS but by changes in the internal state of the nucleus (protons and neutrons jumping shells much as electrons do to emit light). X-rays can be emitted by core electrons following electron capture decay by the nucleus, but that's different and a very specific process. Gammas are emitted by the nucleus. It would be nice to correct this vid, to keep it up to the standard of previous ones. Thanks !

[homosexualitymydearwatson]

You've taught my classes more than my teachers

[ragnkja]

6:54 An error: Xe is element 54. Element 91 is Protactinium, which has an average mass of 231.03588 g/mol, which means that Pa-234 is an isotope which is heavier than average (meaning I suspect it will pretty soon decay as well).

[ScareSans]

if you think about it, radioactivity is just...








*S P I C Y A I R*

[rettavelle]

Not only have all of these awesome chemistry videos caused me to fall in love with Hank, but they have also effectively prepared me for my chemistry semester final!  THANK YOU CRASH COURSE! 

[TheAnachronist]

Gamma rays can occur from pure nuclear state transitions without involving electrons at all, when one isomer decays into a more stable one. Generally we talk about Gamma rays only when there's some sort of nuclear process taking place and X-rays when the process involves electrons.

[ShellPointe]

I've been hoping we would cover nuclear chemistry!!! This is my all time favorite topic. Nuclear pharmacy is like my dream job.

[message]

This is awesome. More evidence that we are living in exponential and information rich times. Keep the knowledge coming!

[medich]

Gamma rays are not generated by transition between electron levels.
The energy difference is too small.
Instead, they are generated by re-arrangement of protons and neutrons within the neucleus. They frequently modeled by shell model, too, although very different form the electric one.

[camillejohnson]

dude you're incredibly helpful but talk so so so fast I can't process what you're saying.

[thdriftwood]

This topic is not easy to process and for him to talk that fast makes it even harder to comprehend.

[mtchllBarrett]

If Thorium-234 loses a beta particle, shouldn't it become Protactinium-234? Xenon only has 54 protons.

[rauketman]

I think that it is misleading to represent only gamma radiation as dangerous. Alpha and beta emitting nuclides are dangerous when they enter the body where they do arguably more damage than gamma. I understand that this is a simplification, however, these videos are usually very good at presenting the whole truth, and not a simplication of it.

Also, your description of gamma decay was incorrect. Gamma rays are electromagnetic radiation emitted from the nucleus of an atom dropping into its ground state. This is analogous to the electron ground state, as you described, but this electron transition is what we define as x-rays.

Also,  Xe should have been Pa in the thorium decay example.

[enderman_of_dm]

Omg. I've finally seen someone make a reference to the Mutant Zombie from Minecraft!

[toasted_mello]

I got covid and had to miss a whole week of university chemistry lectures, you're saving my butt once again, Hank!

[topkis]

I had a test on this on friday, looked everywhere for a radioactivity video and of course its posted just 3 short days later -_-

[vishvakseenichamy]

At 6:53, how come it Xenon has a number of 91 when Thorium had 90 and when it released it's electron?

[tahasilat]

Recommendations for watching crash course:
1. Take notes when you watch the video
2. Pause the video and replay if you don't understand something
3. Set the speed to 0.75. This makes it much easier to understand