atomic structure Flashcards
what are all substances made of
atoms
what is an atom
the smallest part of an elemetn that can exist
how are atoms represented
chemical symbols
how many different elements are there
about 100
how are compound formed
from elements by chemical reactions
what is a chemical reaction
they involve the formation of one or more new substances and often involve w detectable energy change
what are compounds
substance that contains two or more elements chemically combined in fixed proportion ms
how can compounds be seperated into elements
chemical reactions
what is a mixture
two or more elements or compounds not chemically combined together, the properties of each substance is unchanged
how can mixtures be seperated
filtration, crystalisation, simple distillation, fractional distillation and chromatography
what model of the atom was developed following the discovery of the electron
plum pudding model
describe the plum pudding model
ball of positive charge with negative electrons embedded in it
what was concluded from the alpha particle scattering experiment
the mass of the atom was concentrated at the centre and that thr nucleus was charged
what model replaced the plum pudding model
nuclear model
how did neils bohr adapt the nuclesr model
he suggested that electrons orbit the nucleus at specific distances
