History of the Atom Flashcards
Who claimed that elements are made of tiny particles called atoms?
John Dalton - 1803
Who claimed that atoms of one element are identical, while atoms of different elements are different?
John Dalton - 1803
Who claimed that compounds are combinations of two or more different types of atoms?
John Dalton - 1803
Who stated that chemical reactions are the rearrangement of atoms?
John Dalton - 1803
Who experimented with cathrode ray tubes to show that all atoms contain tiny negatively charged subatomic particles (electrons)?
J.J. Thompson (1896)
Who’s plump pudding model of the atom had negatively charged electrons embedded within a positively charged “soup”?
J.J. Thompson (1896)
Who described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all mass is concentrated in?
Enerst Rutherford (1909)
Who’s gold foil experiment disproved Thompson’s atomic model?
Ernest Rutherford (1909)
Who’s experiment proved that the atom had a small, heavy region positive charge inside it with negatively charged electrons being at a great distance from the centre?
Ernest Rutherford (1909)
Who claimed that in an atom, electrons revolve around the positively charged nucleus in a definitive circular path called orbits or shells?
Niels Bohr (1911)
Who claimed that each orbit or shell has a fixed energy and that the circular orbits are known as orbital shells?
Niels Bohr (1911)
Who suggested that an atomic spectrum is created when the electrons in an atom move between energy levels?
Niels Bohr (1911)
Who conceived that the atom is understood as a nucleus with protons and neutrons, assuming almost the entire mass of the atom, with the electrons orbiting the nucleus in their corresponding energy levels?
James Chadwick (1932)
Who conceived that a neutron is an arrangement made up of a proton and an electron, which generates a neutral charge?
James Chadwick (1932)
