Particles Flashcards
(26 cards)
what is a physical change
a change that affects how a substance looks and not it’s identity. easy to reverse
what is a chemical change
a change where a substance turns into another substance. reactants to products
explain the properties of a solid
regular arrangement, vibrate about a fixed position, very close
explain the properties of a liquid
randomly arranged, move around eachother, close
explain the properties of a gas
randomly arranged, move quickly in all directions, far apart
what does the particle theory explain
how matter changes state depending on the energy and forces present between the particles in the substance
what happens when substances are heated
the particles absorb thermal energy which is converted into kinetic energy
limitations of the particle theory
Particle theory considers all particles, irrespective of their state or chemical identity, to be small, solid and inelastic, It doesn’t consider the difference caused by different particles, The theory also fails to consider the intermolecular forces that exist between different particles in different substances
what 3 key ideas was Dalton’s atomic theory based on
Matter is made of atoms which are tiny particles that cannot be created, destroyed, or divided
Atoms of the same element are identical, and atoms of different elements are different
Different atoms combine together to form new substances
what was JJ Thompson’s theory
discovered the electron - ‘Plum pudding’ model shows a sphere with positive charge and negative electrons
explain Rutherford, Geiger and Marsden’s model of the atom
they shot a beam of positively charged particles at a thin sheet of gold foil and based on the plum pudding model, most went straight through but some deflected back
what was the nuclear model of the atom
the atom consists mainly of empty space with the nucleus at the centre and the electrons orbiting in paths around the nucleus
what was Bohr’s model
electrons orbit the nucleus in fixed shells - high energy orbitals are further away from the nucleus
what is each atom made of
subatomic particles (protons, neutrons, electrons)
what is the relative charge and relative mass of a proton
relative charge = +1
relative mass = 1
what is the relative charge and relative mass of a neutron
relative charge = 0
relative mass = 1
what is the relative charge and relative mass of an electron
relative charge = -1
relative mass = 1/2000
what are all substances made of
tiny particles called atoms - the building blocks of all matter
what is the atomic number
the number of protons in the nucleus of an atom
what is the mass number
the total number of protons and neutrons in the nucleus of an atom
how do you find the number of neutrons in an atom
the mass number minus the atomic number
what are isotopes
atoms that contain the same number of protons and electrons but a different number of neutrons
what is an ion
an atom that has an electrical charge, either positive and negative
what is a cation
an atom that loses electrons has more protons than electrons and so has a positive overall charge
