Who is credited with "splitting the atom" in 1917?

Ernest Rutherford was a New Zealand-born British physicist who became known as the father of nuclear physics. Encyclopædia Britannica considers him to be the greatest experimentalist since Michael Faraday. In 1911 he theorized that atoms have their charge concentrated in a very small nucleus, and thereby 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.