# Physic Basic BASICS!

1. Feb 24, 2010

### nobodyuknow

Hey all,

I've just started grade 11 and started studying Physics for the first time, so I have very little knowledge in Physics and find it very difficult to understand things that are given to me during class and reading them off the internet.

Some of my main questions that I have trouble with at the moment is:

What is a Nucleus?
What is a Nuclide?
[STRIKE]What is a Nuclei[/STRIKE]? SOLVED: Plural of Nucleus.

I think Nuclei is plural for Nuclide - but I'm not sure.

What is a Neutron and what charge does it hold?
What is a Electron and what charge(s) does it hold?
What is a Proton and what charge does it hold?

I know these are very simple questions, but I find the information on the internet is too complex and have a lot of information that I find difficult to comprehend.

It'd be great if you could give me about a sentence or two for each question and briefly explain their functions.

Thank you SO MUCH!
~ Aaron

EDIT:

Last edited: Feb 24, 2010
2. Feb 24, 2010

### torquil

A heavy, densely packed collection of protons and neutrons in the middle of an atom. It has positive charge and attracts the electrons around it.

Plural form of nucleus.

This is kind of complicated:
http://en.wikipedia.org/wiki/Nuclide

It is a nuclon that is electrically neutral. Approximately the same mass as the proton.

It is a light particle with a small negative charge. Opposite charge as the proton. These particles move around the nucleus in an atom.

Positively charged particle in the nucleus of atoms.

3. Feb 25, 2010

### nobodyuknow

Thanks so much for the answers! No ones really been able to explain to me what a Nuclide is yet though however. I find it fairly difficult to understand!

~A.

4. Feb 25, 2010

### torquil

The precise definition might be a tad different, but in essence it is the following, at least this is my perception of it:

For each element in the periodic table, there are multiple variants with different nuclei. They differ in the number of neutrons, while the number of protons and electrons are constant for that given element, by definition. The reason I call them different versions of the same element is that variations of the number of neutrons in the nucleus doesn't influence e.g. the chemical properties of the atom. So the difference is mostly "nuclear". These are called different isotopes of that element.

Maybe you have heard of e.g. uranium-235 and uranium-238? Those are both uranium because they have the same number of protons in the nucleus, and the same number of electrons oribiting around. Chemically, the behave approx the same. They are different isotopes of uranium. For nuclear reactions though, there is a big difference.

The set of all nuclides consists of all elements including all the different isotopes of each element. I would say that hydrogen H1 and deuterium H2 (0 and 1 neutron in the nucleus) are different isotopes of hydrogen. U235 and U238 are different isotopes of uranium, and {H1, H2, U235, U238} is a set of nuclides. The set of nuclides for a given element is its set of isotopes.

Torquil

5. Feb 26, 2010

### Claude Bile

Wikipedias answer is fine - "A nuclide (from nucleus, originally from Latin, meaning kernel of a nut) is an atomic species characterized by the specific constitution of its nucleus". That is, a nucleide is a specific species of nucleus containing X protons and Y neutrons.

Torquil is on the mark with everything else.

Claude.

6. Feb 27, 2010

### nobodyuknow

Thanks for the replies. I understand a bit more about Isotopes now, but Nuclides.. they sound a lot like Nucleons? What's the difference between the two?

7. Feb 28, 2010

### torquil

No you mean that nuclides sound a lot like nuclei, not nucleons :-) Nucleons are just the single protons/neutrons, not the whole atomic core.

As wikipedia says, a nuclide is an "atomic species", so it is not only the nucleus. It is an atom, and it has a specific number of protons and neutrons in its nucleus.

So U235 is a nuclide, and U238 is a different nuclide. They are different nuclides because they differ in the constitution of the nuclues. Both are the element/atom Uranium. The word nuclide is used when you care about the number of neutrons in the nuclues.

If I ask you to specify a nuclide, you have to specify an atomic element, and also to say how many neutrons it has. Alternatively, you can specify the total number of nucleons, because I can derive the number of neutrons from that, since I know the number of protons from the name of the atomic element.

If you are asked to specify just some element, then you don't have to specify the number of neutrons. You can just say e.g. Carbon.

Torquil