atoms
relative charge of a proton
+1
relative mass of a proton
1
relative charge of a neutron
0
relative mass of a neutron
1
relative charge of a electron
-1
relative mass of electron
1/2000
atomic number
the number of protons inside the necleus of an atom
mass number
the number of protons and neutrons inside the necleus of an atom
how to calculate neutrons
take the bottom number from the top number
shell 1
2 electrons
shell 2
8 electrons
shell 3
8 electrons
shell 4
whatever is left
group number =
number of electrons in the outer shell
magnesium + oxygen =
magnesium oxide
3 types of ionic bond
ionic, covalent and metallic
ionic bond
formed when atoms join together as a result of gaining or loosing electrons
covalent bond
formed when atoms join together as a result of sharing electrons
metallic bond
the bonding holding metals together formed by the metal having ions in a sea of delocalised outer electrons
what did democritus discover
400BC- claimed atoms cannot be split
John dalton discovered?
1803-suggested atomic theory and came up with theories that atoms were tiny particles, unsplitable, which made up elements
JJ Thompson discovered?
1898-discovered electrons and proved that atoms can be split.
Ernest rutherford discovered
1909-used experiment work to develop the necleur model in which most of the mass is concentrated in the positivly charged necleus with electrons orbiting the necleus
1917?
discovered positive charge exists as individual protons
Niels bohr?
1913-discovered that electrons could only travel along certain shells
James Chadwick
1932- devised an experiment that showed the existence of neutrons also found in the necleus.
mobile phase
where the molecules can move this is a liquid or gas
stationary phase
where the molecules cant move this can be a sold or really thick liquid
Rf values
distance travelled by substance ➗
distance travelled by solvent
isotopes
atoms of the same element with different masses. they have the same number of protons and electrons but different numbers of neutrons. SAME chemicak reactions
relative atomic mass
(% x isotope mass) + (% x isotope mass) ➗100