Atoms and Atomic Structure

Before Rutherford, scientists assumed that the atom was a single particle. Rutherford presented his revolutionary, physical atomic model that suggested an atom consists of a central charge (the term 'nucleus' was coined after Rutherford's model was presented) that is surrounded, presumably, by a cloud of orbiting electrons. He showed that most of an atom's mass was located in the atom's nucleus.

Rutherford's model was later improved upon by Niels Bohr, father of the Bohr-model. Rutherford made no connection to an element's atomic number and the number of protons within an atom's nucleus; however, his atomic model paved the way for the discovery of this correlation only a couple years after his model was designed.

Transition metals.

A net postive charge

Boron has 3 valence electrons.

Democritus

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