models
So as to explain the properties of atoms.
element
by number of protons and nuetrons
Because, atoms are so small they can fit on the tip of a pencil.
Scientists make models to describe them.
21 different kinds of atoms
They view atoms through an electron microscope.
Atoms are the topic of interest for many scientists.
Under normal conditions, i.e. non-ionic, the number of protons is equal to the number of electrons.
Gaseous oxygen at normal Earthly conditions is composed of diatomic molecules. At very high temperatures, these can decompose into individual atoms. In other words that means that it is made of molecules.
microscope
So as to explain the properties of atoms.
Under normal conditions, carbon will bond with a maximum of 4 other atoms.
periodic table
Atoms were found to be divisible after all . But scientists discovered that the atoms were made of smller perticles , called subatomic particles.
"H" is the chemical symbol for Hydrogen. "H2" is the symbol for a molecule that contains two atoms of hydrogen. Under normal conditions in the Earth's atmosphere, hydrogen gas is usually found in the form of molecules consisting of two atoms.
Chemists.