Atomic Structure Flashcards
What did Robert Boyle propose?
1661 some substances could not be made simpler (chemical elements)
What did John Dalton suggest?
Elements were made of indivisible atoms
All atoms of an element have same mass
Atoms could not be broken down
What did Henri Becquerel discover?
radioactivity
What did Henri Becquerel discover?
radioactivity
What did JJ Thomson discover?
electron and plum pudding (sphere of positive charge with small negative charges distributed evenly within it)
What did Ernest Rutherford find?
Most of the mass and positive charge of atom was in a tiny central nucleus
Electron shell model (scattering experiment)
What does electrostatic forces of attraction do?
Hold electrons and protons together in the atom
What is the definition of
What is the mass number?
sum of protons and neutrons
What is the atomic number?
number of protons
What is the mass of electrons?
1/1840
Definition of isotope?
atoms of the same element with the same number or proton but different number of neutrons
What did Niels Bohr propose?
1913: shells of electrons orbiting positive nucleus
What did James Chadwick discover?
1932: neutron
What is the definition of relative atomic mass?
The mean mass of an atom of an element, relative to 1/12 of the relative atomic mass of Carbon -12
