c1: atomic structure Flashcards
(20 cards)
what is an atom
smallest part of an element that can exist
what is Daltons modal of the atom
atoms as solid spheres that could not be divided into smaller atoms
what is the plum pudding model of the atom
sphere of positive charge with negative electrons embedded in it
what did scientists discover in the alpha scattering experiment
some alpha particles were deflected by the gold foil
showing that an atoms mass and positive charge must be concentrated in one small space
describe the nuclear model of the atom
dense nucleus with electrons orbiting it
what did Niels Bohr discover
electrons orbit in fixed energy levels
( shells )
what did James Chadwick discover
uncharged particle called the neutron
where are protons and neutrons
in the nucleus
what is the relative mass of each sub-atomic particle
proton: 1
neutron: 1
electron: 0
what is the relative charge of each sub-atomic particle
proton: +1
neutron: 0
electron: -1
how can you find out the number of protons in an atom
the atomic number on the periodic table
how can you calculate the number of neutrons in an atom
mass number - atomic number
why do atoms have no overall charge
equal number of positive protons and equal number of negative electrons
how many electrons would you place in the first, second and third shells
up to 2 in the first shell
up to 8 in the second shell
up to 8 in the third shell
what is an element
substance made of one type of atom
what is a compound
substance made of one or more than one type of atom chemically joined together
what is a mixture
two or more substances not chemically combined
what are isotopes
atoms of the same element
what are the 5 physical processes that can be used to separate mixtures
filtration
crystallization
distillation
fractional distillation
chromatography
what is relative mass
the average mass of all the atoms of an element
