paper 1 Flashcards
what are compounds and how can they be separated
Compounds are formed from elements by chemical reactions
Compounds contain two or more elements chemically combined
Compounds can only be separated into elements by chemical reactions
what are mixtures and how can they be separated
A mixture consists of two or more elements or compounds not chemically combined
together.
Can be separated by: filtration, crystallisation, simple distillation, fractional distillation
and chromatography. These are physical processes, so do not involve chemical reactions
what was the first theory of the atom
thought to be tiny spheres that could not be divided
what model supported the discovery of the electron
plum pudding model
what was the conclusion of the alpha particle scattering experiment
the mass of an atom was
concentrated at the centre (nucleus) and that the nucleus was positively charged
what happened during the alpha particle scattering experiment
A beam of alpha particles was aimed at very thin gold foil
the positively charged alpha particles were being repelled and deflected by a
small concentration of positive charge in the atom (nucleus) although the majority of the beams went straight through
what did neil Bohr suggest
suggested electrons orbit the nucleus at specific distances
what did james chadwick prove
existence of neutrons
how are elements arranged
according to atomic (proton) number
what is the relationship with elements in same group
they have same amount of electrons in outer shell
giving them similar chemical properties
How did dimitri mendelev order his periodic table
ordered in terms of atomic mass and left gaps for elements that he thought had not been discovered yet
what made it possible to explain that basing on atomic weights was not always correct
the discovery of isotopes
what are metals
elements that react to form positive ions
what are non metals
elements that do not form positive ions
what is the name of group 1 elements
alkali metals
