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Put your knowledge to the test about these terms related to the atom!

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The particle in the center of an atom that holds a positive

charge and distinguishes

what element it is. No two

elements have the same

amount of protons.

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A proton is a tiny particle, smaller than an atom. Protons are too small to see, even with an electron microscope, but we know they must be there because that's the only way we can explain how atoms behave. To give you an idea how small a proton is, if an atom was the size of a football stadium, then a proton would still be smaller than a marble.

Pretty much all of the protons in the universe probably got made very soon after the Big Bang. At first there was no stuff, just a lot of loose energy shooting around everywhere in the form of photons (light) and larger particles like photons called bosons. These early bosons had tons of energy and a lot of them broke apart into protons and anti-protons. Most of these protons and anti-protons eventually lost energy and hooked back up into bosons again, but some of the anti-protons seem to have gotten lost somewhere, and all the mass in the Universe comes from these left-over protons.

All protons, everywhere in the universe, are exactly the same, and pretty much all of them are inside atoms. Different atoms have different numbers of protons; what makes an atom be a helium atom, or a gold atom, or an oxygen atom depends on how many protons it has, not what kind they are.

Protons make the nucleus, or center, of an atom. The simplest atoms - hydrogen atoms - have a nucleus made of just one proton. But most atoms have more than one proton, and at least one neutron to go with each proton (some have more than one).

Protons are actually made of even smaller invisible particles, called quarks. Each proton has three quarks, two up quarks and one down quark. A strong nuclear force sticks the quarks together. Most of the mass of a proton comes from this strong nuclear force, rather than from the quarks.

Because a proton has two up quarks and only one down quark, it has a positive charge, like the positive end of a magnet. Two things that have positive charges push away from each other, so the protons in an atom are always pushing away from each other. They need the neutrons to pull them together. The neutrons help to stick the protons together, using the strong nuclear force. The heaviest atom that exists in nature is uranium, with 92 protons. Even the neutrons and the strong nuclear force can't hold together more protons than that for more than a few seconds.

Bibliography and further reading about atoms and protons:

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Autzen Stadium, in Eugene Oregon, seats 54,000 people A proton is a tiny particle, smaller than an atom. Protons are too small to see, even with an electron microscope, but we know they must be there because that's the only way

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Particles with a negative charge that surround the nucleus in orbitals. There is the same amount of electrons as protons are in the atom.

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There are different ideas of what an electron is. One idea syas that an electron is part of an atom. Depending on the kind of atom, an atom can have 1 to 103 electrons. Each electron is extremely tiny.

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The particle in the center of the atom

that holds no charge. They play a role in

the radioactivity and mass of an atom.

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The area, in a specific shape,

around an atom that holds

electrons.

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Electrons on the outer-

most shell of the atom's

orbital. Important in bonding.

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Atoms are the smallest unit of matter and the

basic building blocks of everything! They are

made up of Neutrons, Electrons, and Protons.

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What is an atom? Atoms are building blocks. If you want to create a language, you'll need an alphabet. If you want to build molecules, you will need atoms from different elements. Elements are the alphabet in the language of molecules.

Each element is a little bit different from the rest. In English, you know that "B" is different from "C." In chemistry, "B" is also different from "C" because boron (B) and carbon (C) are different elements with atoms that have different structures. Atoms are defined as the smallest units of matter that have the properties of an individual element.

Are there pieces of matter smaller than an atom? Sure. Atoms are made up of smaller and even smaller particles of matter. However, those smaller particles don't have the properties of an element. The electrons in a gold (Au) atom are the same as the electrons in an atom of neon (Ne). In chemistry, we like to study atoms because the Universe revolves around the properties of elements, not necessarily the properties of an electron or proton.

For example, let's say you have bar of gold. You know that bar is made of matter because everything is made of matter. Because it is pure gold, there are only gold atoms in the bar. If you only had one atom of gold in your hand, it would have the same properties as every other gold atom in that bar. But what if you only had one electron from a gold atom? That electron would not have the properties of gold anymore. It would just be an electron doing electron stuff. The atom is the smallest unit that has the properties of an element.

We can teach you about the general structure of an atom, but you need to study atoms from different elements to really learn how atoms work.

Let's work with the alphabet idea again. If you read a book, you will find words on each page. Letters make up those words. In English, we only have twenty-six letters, but we can make thousands of words. In chemistry, you are working with almost 120 elements. When you combine them, you can make millions of different molecules.

Molecules are groups of atoms in the same way that words are groups of letters. An "A" will always be an "A" no matter what word it is in. A sodium (Na) atom will always be a sodium atom no matter what molecule it is in. While atoms from different elements have different masses and structures, they are all built with the same parts. Electrons, protons, and neutrons are the basic subunits for all atoms across the Universe.

If you want to do a little more thinking, imagine the smallest particles of matter. Super-tiny subatomic particles are used to create the parts of atoms. Protons, neutrons, and electrons can then organize to form atoms. Atoms are then used to create the molecules around us. As we just learned, there are almost 120 elements that can be found in the molecules we know. Smaller molecules can work together and build macromolecules. It just goes on. Everything you see or imagine is built from something else.

You could start really small...
- Particles of matter
- Atoms
- Molecules
- Macromolecules
- Cell organelles
- Cells
- Tissues
- Organs
- Systems
- Organisms
- Populations
- Ecosystems
- Biomes
- Planets
- Systems with Stars
- Galaxies
- The Universe
...And finish really big.

Wow! All of that is possible because of atoms.

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What is an atom? Atoms are building blocks. If you want to create a language, you'll need an alphabet. If you want to build molecules, you will need atoms from different elements. Elements are the alphabet in the language of molecules. Each element is a little bit different from the rest.