C1 atomic structure and the periodic table Flashcards
what is an atom
they make up all substances and are the smallest part of an element that can exist
what are compounds
more than one element chemically bonded together
what is a mixture
two or more elements combined together but not chemically bonded
name some ways that mixtures can be separated
filtration, crystallisation, simple distillation, fractional distillation, chromatography
what were atoms first thought as
tiny spheres that could not be divided
what was the plum pudding model
atom is a ball of positive charge with negative electrons embedded in it
what is the alpha particle scattering experiment
-beam of alpha particles was aimed at very thin gold foil and their passage through was detected
-some of the alpha particles emerged from the foil at different angles and some even came back
-the positively charged alpha particles were being repelled and deflected by a small concentration of positive charge in the atom (nucleus)
what did Neil Bohr suggest about atoms
electrons orbit the nucleus at specific distances
what did James Chadwick suggest about atoms
provided the evidence to show the existence of neutrons within the nucleus
what is the atomic number
number of protons in an atom of an element
what is relative atomic mass
average value that takes account of the abundance of the isotopes of the element
how are groups on the periodic table ordered
order of atomic number and all have the same amount of electrons in there outer shell and therefore similar chemical properties
how did john Dimitri order the periodic table
-in order of atomic mass
-realised similar properties occurred every eighth element
how did Dimitri Mendeleev order the periodic table
-ordered in order of atomic mass but not always
-left gaps for elements that he thought had not been discovered yet
where are metals found on the periodic table
found towards the bottom left of the periodic table
