Particle Model Of Matter Flashcards
What is latent heat of vaporisation?
Energy needed for a substance to change from a liquid to a gas (Evaporate)
What did Niels Bohr discover?
Electrons orbit the nucleus at specific distances
What is ionising?
Knocking electrons from atoms
What did JJ Thompson 1897 discover?
Discovery of electron
Led to plum pudding model
Atom as a ball of (+) charge with embedded electrons
What did James Chadwick discover (1932) ?
Found that within the nucleus there was another particle = neutron
What are isotopes?
Same number of protons, different number of neutrons. Different mass number but same atomic number.
Why might the energy level of an electron change?
When atom emits or absorbs electromagnetic radiation
Why is electromagnetic radiation emitted?
When an electron drops to a lower energy level
What happens to a nucleus when it absorbs electromagnetic radiation?
It moves electrons to a higher energy level, further from nucleus
How are electrons arranged?
Arranged at different distances from nucleus, in different energy levels
What was Rutherford and Marsden theory 1905?
If plum pudding was correct, heavy positively charged alpha particles would pass straight through, most but not all did
What happened in Rutherford and Marsdens experiment?
Some alpha particles deflected so they must have come close to a concentration of charge, unlike spread out charge of plum pudding. Some alpha particles deflected back so must’ve been repelled by same charge alpha particles carried, repelling charge must’ve been much heavier than alpha particle, or it would’ve passed through
What did Ernest and Marsden conclude?
Fired alpha particles through gold foil and concluded: mass of atom concentrated in positive charged nucleus, electrons surrounded nucleus
Where are electrons found?
Orbiting the nucleus in shells
What is latent heat of fusion?
Energy needed for a substance to change from solid to a liquid (melt)
