Periodic Table: Atomic Structure, Atomic Number, Atomic Mass

What are atoms?

Atoms are the basic building blocks of matter that make up everyday objects. A desk, the air, even you are made up of atoms!

There are 90 naturally occurring kinds of atoms. Scientists in labs have been able to make about 25 more.


Atoms are made out of 3 different particles:

1. Proton- carry a positive charge

  • There are 3 quarks in each proton, and the quarks are held together by gluons

2. Neutron-carry no charge

  • Scientists discovered the neutron in 1932
  • In 1968 they discovered tiny things called quarks in the neutron. Just like protons, gluons hold them together

3. Electron- carry a negative charge

  • Electrons are extremely small and very light
  • It is easy to strip off electrons off of atoms and use them for electrical power and in devices such as television sets
  • Electrons can be used to probe inside of atoms. Higher energy electrons can detect smaller features inside atoms. Scientist learn about the inside of atoms by watching how electrons bounce off the atom, and by how the atom changes as a result of being hit by an electron

4. Central part of the atom

  • The nucleus is the massive center of the atom
  • It was discovered in 1911 but was not identified by its parts until 21 years later


Fact 1
Fact 1

The Element Hydrogentableofelements.png

Atomic Number: 1
Atomic Weight: 1.00794
Melting Point: 13.81 K (-259.34°C or -434.81°F)
Boiling Point: 20.28 K (-252.87°C or -423.17°F)
Density: 0.00008988 grams per cubic centimeter
Phase at Room Temperature: Gas
Element Classification: Non-metal
Period Number: 1 Group Number: 1 Group Name: none

What is the difference between atoms and elements?

Get ready for an imperfect analogy.
Imagine going to an ice cream store. Let's say that they have 30 different flavors of ice cream. Those are elements, the things that I have available to build my dessert from. The smallest amount of ice cream that the store will sell to me is a scoop. This is an atom. If I want, I can put two or more scoops of ice cream together. This is a molecule. If my molecule has more than one flavor of ice cream, I can call it a compound.
So, in summary:
element - a basic substance that can't be simplified (hydrogen, oxygen, gold, etc...)
atom - the smallest amount of an element
molecule - two or more atoms that are chemically joined together (H2, O2, H2O, etc...)
compound - a molecule that contains more than one element (H2O, C6H12O6, etc...)
What's wrong with the ice cream analogy? Splitting an atom creates different elements (split an oxygen atom and you don't have oxygen any longer). Splitting a scoop of ice cream results in smaller blobs of the same flavor. For the analogy to hold true, the flavor of the ice cream would have to change when you split a scoop (the chocolate 'element' would have to change into some other 'element' (flavor).


1. A proton has what kind of charge?
2. An electron has what kind of charge?
3. A neutron has what kind of charge?
4. Because the number of protons is equal to the number of electrons in a neutral atom, the atomic number is also the number of electrons in the atom
True or False

Sources:,,, google images,