c1.1 + c1.2 Flashcards
what are the three states of matter?
solid, liquid and gas
what takes place at the melting point?
melting and freezing
what takes place at the boiling point?
boiling and condensing
describe the particle arrangement in a solid
- particles are close together
- regularly arranged
- vibrate in fixed positions
describe the particle arrangement in a liquid
- close together
- random arrangement
- can move/flow past each other
describe the particle arrangement in a gas
- spread apart
- random arrangement
- free to move past each other
what is a chemical change?
requires a chemical reaction and for there to be a change from reactants to productsv
what is a physical change?
requires energy and involves a change in state rather than a change to particles (eg melting, freezing)
explain the limitations of the particle model
the particle model doesnt take into account:
- forces of attractions between particles
- the size of particles
- the space between particles
what was Dalton’s atomic model?
- atoms of an element are identical
- atoms cant be divided
- atoms make up all substances
- atoms join to make new substances
explain Thomson’s plum pudding model
- atom is positively charged sphere with electrons dotted inside
what was Rutherford’s atomic model?
- atoms made up of a positive nucleus with negative electrons
- also discovered the proton
what did Bohr discover/propose?
that electrons occupy shells around the nucleus, preventing it from collapsing
explain the gold foil experiment
- geiger and marsden shot beams of positively charged alpha particles at a gold foil sheet
- some particles deflected to the side but some deflected straight back (they would have gone straight through according to plum pudding model)
- led to the theory of a nucleus existing
describe today’s atom
- a positive nucleus surrounded by negative electrons
- most of the mass is concentrated in the nucleus
- nuclear radius is much smaller
