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Theorized that solid forms of matter are composed of indivisible elements shaped like triangles. -
The atom was the basic building block of matter. -
Illustrate the relative positions and motions of the planets and moons. -
Developed the theory that all metals were formed of sulfur and mercury. -
He demonstrated that matter is made up of tiny particles that he called corpuscles. -
Matter was composed of atoms that were not created or destroyed during chemical reactions. -
Defined an atom to be a ball-like structure as the concepts of atomic nucleus and electrons were unknown. -
All matter was compromised of invisible and indestructible atoms with distinct masses and properties. -
Invented the periodic table. -
Two hypotheses - Equal volumes of gas contain equal numbers of molecules; Elementary gases were composed of two atoms. -
Discovered the radioactive elements polonium and radium. -
All atoms contain tiny negatively charged substance particles or electrons. -
Depicts the electrons as negatively charged particles embedded in a sea of positive charge. -
Mathematically proved the existence of atoms. -
Accurate determination of the charge carried by an electron. -
Described the atom as having a tiny, dense, and positively charged core called the nucleus. -
Proposed a theory for the hydrogen atom based on quantum theory. -
The atomic number of an element is the number of positive charged in the atomic nucleus. -
Developed an idea that a strong force in the nucleus holds the neutrons and protons together. -
Represents the area around an atom's nucleus where electrons are most likely to be found. -
Discovered the neutron.