Here's a breakdown of the historical development:

* Ancient Greek Philosophers (5th Century BC): Philosophers like Democritus and Leucippus proposed that matter was composed of indivisible particles called "atomos" (meaning "uncuttable"). This was a philosophical idea, not based on scientific evidence.

* John Dalton (1803): Dalton formulated the first modern atomic theory, which was based on experimental observations. He proposed that elements are composed of atoms, which are identical in mass and properties. This theory was groundbreaking and paved the way for further atomic research.

* J.J. Thomson (1897): Thomson discovered the electron, proving that atoms are not indivisible as Dalton had proposed. This led to the development of the plum pudding model of the atom.

* Ernest Rutherford (1911): Rutherford conducted the famous gold foil experiment, which demonstrated that the atom has a small, dense, positively charged nucleus surrounded by negatively charged electrons.

Therefore, while ancient Greek philosophers had the initial idea of atoms, it was John Dalton who first proposed a scientific theory of the atom based on experimental evidence. However, subsequent discoveries by Thomson and Rutherford proved that Dalton's model needed to be revised.

So, depending on how you define "prediction," you could argue that the first prediction was made by Democritus, but it was Dalton who first provided a scientific theory backed by evidence.