What is an atom?
Atoms are the basic unit of chemical element.
They are the basic building blocks of ordinary matter.
Atoms are composed of particles called protons, electrons, and neutrons.
The protons carry a positive electrical charge, the electrons carry out
a negative electrical charge, and the neutrons carry no electrical
charge. Protons are the atomic number. Protons and Neutrons make up the
mass number ( PROTON + NEUTRON = MASS NUMBER.) The Electrons equal the
same number as the protons.
The element symbol is abbreviation from the elements name. In the picture below it shows the atomic number on top and the Atomic mass number on the bottom. On others it would have the name of the element between the element symbol and the atomic mass.
Isotopes
An isotope has a different number of neutrons an a atom. Which means the atomic mass number will change but the proton number will not changes. For example in the picture below it shows carbon having three different atomic mass numbers, which means it is an isotope.
