Developed the first model of the atom that showed the structure of the inside of an atom.

J. J. Thomson

Explanation:

J. J. Thomson proposed in 1904 a new model of the atom that substitutes Dalton's model, and although erroneous, this model remained valid for years and served as the basis for new postulates and research on the subject. This is because Thomson discovered (after his experiments with cathode ray tubes) the electron and showed that the atom was not indivisible.

This model was also known as the plum pudding model, because Thomson thought the electrons were immersed in the atom of positive charge that counteracted the negative charge of the electrons. Just like the raisins embedded in a pudding or bread.

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray