A small piece of sodium metal is placed in a flask of chlorine gas. A little water helps expose the sodium so it can react with the chlorine gas. The reaction releases a lot of heat as the ionic ...

The structure of the atom is what ... in circles called energy levels. Their mass is so small it is nearly zero. Positively charged particles that are contained in the nucleus of the atom (the ...

After tracing many particles and examining the patterns, Rutherford deduced that the atom must have nearly all its mass, and positive charge, in a central nucleus about 10,000 times smaller than ...

it becomes a negatively-charged ion A helium atom has two electrons in an energy level outside the nucleus. The atom is neutral as it has two positive protons and two negative electrons.

Bohr’s Model of an Atom: Danish Physicist Niels Bohr received his Ph.D. from the University of Copenhagen in 1911. In 1922, he was awarded the Nobel Prize in Physics for his work on the atom’s ...

When two hydrogen atoms get close enough, the electron from each atom ... energy level of the atoms. When two hydrogen atoms and an oxygen atom get close enough, the electron from each atom feels an ...