"He was an old boy who had been with Rutherford when he split the atom"
Ernest Rutherford 1908
Public DomainErnest Rutherford 1908 - Credit: US Library of Congress

Ernest Rutherford, 1st Baron Rutherford of Nelson (1871 – 1937) was a British chemist and physicist who became known as the father of nuclear physics.  He was born in New Zealand, and gained a BA, MA and BSc from the University of New Zealand.  In 1895 he travelled to England for postgraduate study at Cambridge University.  In 1898 he became Professor of Physics at McGill University in Montreal, Canada.  In this role, he discovered the concept of radioactive half-life, proved that radioactivity involved the transmutation of one chemical element to another, and differentiated and named alpha and beta radiation. He was awarded the Nobel Prize in Chemistry in 1908 "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances."

Rutherford's atom model
GNU Free Documentation LicenseRutherford's atom model - Credit: Jean-Jacques MILAN

In 1907 he became chair of physics at the University of Manchester.  In 1911, he theorized that atoms have their positive charge concentrated in a very small nucleus, and pioneered the Rutherford model of the atom.  He is widely credited with first "splitting the atom" in 1917 in a nuclear reaction between nitrogen and alpha particles, in which he also discovered and named the proton.  This led to the first experiment to split the nucleus in a fully controlled manner, performed by two students working under his direction, in 1932. The chemical element rutherfordium was named after him in 1997.