Hydrogen the simplest atom

Atomic number Symbol for hydrogen - Atomic mass 

An atom of hydrogen consists of one proton (constituting the nucleus) and one electron. This simplicity of atomic structure means that H is of great importance in theoretical chemistry, and has been central in the development of atomic and bonding theories (see Chapters 1 and 2). The nuclear properties of the hydrogen atom are essential to the technique of H NMR spectroscopy (see Section 4.8). 

In this chapter, we extend our discussions of hydrogen, looking at the properties of the H+ and H ions, properties and reactivity of H2, and aspects of binary hydrides. 

A binary compound is composed of only two different elements. 

---

Rutherford s model of atomic structure left one major problem unsolved. It was known that hydrogen, the simplest atom, contains only one proton and that the helium atom contains two protons. Therefore, the ratio of the mass of a helium atom to that of a hydrogen atom should be 2 1. (Because electrons are much lighter than protons, their contribution to atomic mass can be ignored.) In reality, however, the ratio is 4 1. Rutherford and others postulated that there must be another type of subatomic particle in the atomic nucleus the proof was provided by another English physicist, James... 

---