P4/Atomic Structure Flashcards
what is the radius of an atom?
1x10-10 m
which two particles make up the nucleus of an atom?
protons and neutrons
where, in an atom, are the electrons found?
orbiting the nucleus
the radius of the nucleus is what fraction of the radius of the atom?
1/10,000
what do we call the different distances that the electrons can be from the nucleus?
energy nucleus
how can an electron move to a higher energy level?
when the atom absorbs electromagnetic radiation
which number tells us the number of protons?
the atomic number
how can you work out the number of neutrons in an atom?
mass number-atomic number
what do we call atoms of the same element that have different numbers of neutrons?
isotopes
what do atoms turn into if they lose one or more of their outer electrons?
positive ions
before the discovery of the electron, atoms were thought to be what?
tiny spheres that could not be divided into anything smaller
the discovery of the electron led to which model of the atom?
the plum pudding model
the plum pudding model suggested that the atom is a ball of positive charge with negative electrons located where?
embedded everywhere in it
the results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was what?
positively charged
the nuclear model replaced what?
the plum pudding model
Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus in what?
shells
later experiments led to the idea of which particle?
the positively charged proton