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440
Aristotle
Aristotle did not believe that atoms could make up all things in nature. -
440
Democritus
Democritus believed that atoms are small and hard particles. He called them atomos meaning not able to be divided. -
Dalton
Dalton beleived that all substances are made of atoms. Atoms cannot be created, divided or destroyed. Atoms of the same element are exactly alike. Atoms of different elements are different. Atoms join together to make new substances. -
Mendeleev
Mendellev arranged the elements into a periodic table. Arranged elements by increasing atomic mass. He Used the pattern of the periodic table to predict new elements. -
Thomson
Thomson believed that there are small, negatively charged particles inside an atom. An atom is a positive sphere with electrons mixed through it. -
Moseley
Moseley rearranged the periodic table by atomic number and corrected some of the flaws in the earlier periodic table. -
Rutherford
Rutherford believed that there is a small, dense, positively charged nucleus. The nucleus is made of positively charged particles called protons. -
Bohr
He believed that electrons traveled around the nucleus in circular paths. And each electron circles a certain distance from the nucleus. -
Aristotle
He helped stufy the periodic table. If he did not study it we would never have known about the periodic table elements. Thats how he helped.
