alpha scattering experiment and nuclear model Flashcards
what happened in 1897?
scientists discovered atoms contained tiny negatively charged particles called electrons
what did plum-pudding model state?
atom was a ball of positive charge with negative electrons embedded in it
what happened in the alpha-scattering experiment?
scientists fired alpha particles at thin gold foil
most particles passed through without changing direction, what did this mean?
most of atom is empty space
some particles passed through but deflected, what did this mean?
centre of atom must have a positive charge that repelled alpha particles
some particles bounced straight back, what did this mean?
most of the mass of the atom is concentrated at the centre/ nucleus
as a result of the alpha scattering experiment, what was produced?
nuclear model of an atom
positive nucleus at the middle, with most of the atom being empty space with a cloud of negative electrons
what did niels bohr propose?
idea that electrons orbited nucleus at specific distances/ energy levels
what did james chadwick do?
discovered nucleus contains neutrons
