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 ...

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.

But a new kind of clock, based not on electrons but on the nucleus of an atom, is on the horizon ... While most atomic clocks rely on changes in energy levels of electrons outside the nucleus ...

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 ...

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 ...