The most obvious piece of equipment a receptionist uses is a telephone, but there is a lot of variety in types and styles, from phone systems with a few lines to switchboards with multiple lines.
Modern Atomic Theory Bohr's model of the atom is important because it introduced the concept of the quantum in explaining atomic properties. However, Bohr's model ultimately needed revision becuase it failed to explain the natue of atoms more complicated than hydrogen.rwin Schrodinger developed the equation which is used today to understand atoms and molecules-the Schrodinger Equation (1926) Erwin Schrodinger took the ideas developed by de Broglie, Heisenberg and others and put them together in a single equation that is named after him.
(How do atoms form?) What is the biggest atom? The smallest atom? If by biggest and smallest, you mean mass (which is a measure of how much matter is there), then the smallest is the hydrogen atom with one proton and one electron. Since electrons are about 2000 times less massive than protons (and neutrons), then the mass of an atom is mostly from the protons and neutrons.