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Radioactivity - Concept

Teacher/Instructor Kendal Orenstein
Kendal Orenstein

Rutger's University
M.Ed., Columbia Teachers College

Kendal founded an academic coaching company in Washington D.C. and teaches in local area schools. In her spare time she loves to explore new places.

Radioactivity is a spontaneous process in which atoms with unstable ratios of protons and neutrons in their nuclei decompose into forms with higher stability. Radioactivity is unique because atoms can change their identities by altering the number of protons in their nuclei.

Alright so we're going to talk about the different types of reacti- reactivity that we might be seeing when dealing with nuclear reactions, so we know nuclear reactions are things that happen within inside the nucleus okay so these are things that happens with protons and neutrons and then they actually emit this energy out into the atmosphere.

What type of energy are we talking that that they emit? Well they can emit things called alpha particles this is one of them alpha particles we're going to we're going to start seeing showing them as this Greek symbol for alpha whereas particles are of the helium nuclei. What that means is it has 4 a maximum number of 4 [IB] 2 protons and 2 neutrons. You might see it looking like this or you might see it looking like this with the alpha sorry this is alpha particle. It has a charge of plus 2 because remember that alpha as a helium nuclei, nuclei do not have nuc- they don't have electrons around them so the charge of plus 2 is telling has 2 protons. Because it has two protons it has a mass of 6.64 times 10 to neg- negative twenty fourth kilograms this might seem ridiculously small because it's 10 to the negative twenty fourth, but actually this is a relatively large particle compared to like many other particles that are emitted so this is a pretty big particle and actually so when nuclear reacti- nuclear reactions emit alpha particles, they're not dangerous to us at all they actually can be blocked by things as small as thin as paper so they our clothing can block them they actually are pen- they don't have a high penetrating power so we actually shouldn't be nervous when dealing with alpha particles or alpha decay.

The second type of particle that might be emitted is beta particles and you'll see this Greek letter B indicating that it is a beta particle. And what beta particles are also called they are electrons they're high speed electrons that might be emitted when dealing with nuclear reaction so because they're electrons they might they can be denoted having a mass number of zero because comparatively, the mass of electrons are nothing and they have a charge of negative 1 so or you might see this B saying the same thing but they are identical to each other saying this is the beta particle same thing. The charge of beta particles are -1 charge and the mass is pretty small 9.11 times 10 to the twenty eighth kilograms very small compared to the to heat alpha particle and things that can block is [IB] not that dangerous but things behind with the sticker foil is able to block it so it's really not that terrible for us. We can you know a lot of things are able to block the electrons even though they seem relative like can ridiculously small so we can actually block those from us too.

The main most dangerous kind of radioct- radia- radiation that's going to be evolved from emitted from radioactive materials or a nuclear reactions are gamma rays. Gamma rays that symbol for gamma is an upside down looks like a sideways alpha and this is high energy electromagnetic radiation and these things like if you could think of something along the lines of x-rays that's electrometrically electromagnetic radiation also it's actually more intense than x-ray so when you're going to get your x-ray from like the dentist and they make you put on an apron on to block had that that lead, that lead actually blocks these x-rays. These actually have more penetrating power than x-rays that's actually those can actually be blocked can penetrate through that lead some of it can so it's really really dangerous for us. The symbol may look like this it has no mass it has no charge has a charge of zero has no mass and to block it lead partially blocks it concrete definitely blocks it that's when you think when you see like nuclear power plants you'll see them you'll have like you'll see the big the big concrete buildings that's to block out the gamma rays and also in Chernobyl to stop the actual radiation to radiation affecting the atmosphere, they poured poured tons and tons of concrete on on the reactors to block that gamma radiation so it wouldn't escape so concrete actually is a good blocker of gamma rays but these are very very dangerous that they do get to our skin they actually can can mutate our DNA and then in effect like have our children offspring or have mutations and so that gamma rays are very dangerous in that way.

So these are the three types of radioactivity that you'll see when dealing with nuclear reactions.