C1 Atomic Structure Flashcards
John Dalton’s discovery
(start of the 19th century) Atoms were first described as solid spheres
JJ Thomson’s discovery
(1897) Plum pudding model-the atom is a ball of charge with electrons scattered
Ernest Rutherford’s discovery
(1909) Alpha scattering experiment-mass concentrated at the centre; the nucleus is charged. Most of the mass is in the nucleus. Most atoms are empty space
Niels Bohr’s discovery
(1911) Electrons are in shells orbiting the nucleus
James Chadwick’s discovery
(1940) Discovered that there are neutrons in the nucleus
Isotopes
Atoms of the same element with different numbers of neutrons
What determines the way an element will react?
The number of electrons in the outermost shell of an element’s atoms