atoms and isotopes Flashcards
give an approximation for the radius of an atom
1x10 power of 10 meters
what are 3 subatomic constituents of an atom
.proton
.nuetron
.electron
where is most of the mass of an atom concentrated
in the nucleus
approximately what proportion of the total radius of an atom is the radius of the nuceleus
1/10,000
describe the arrangements of protons,nuetrons and electrons in an atom
.the protons and nuetrons are found in the atoms nucleus
.the electrons are found in discrete energy levels around the nucleus
what type of charge does the nucleus of an atom have
why
.positive charge
. the nucelus contains protons and nuetrons
.protons have a positive charge
.nuetrons have no charge
give 2 ways , that an atoms electron arrangement can be changed
. absorbing electromagnetic radiation
. emmiting electromagnetic radiaiton
explain how an atoms electron arrangment changes when it absorbs EM radiaiton
. electrons move further away from the nucleus
.they move to a higher energy level
explain how an atoms electron arrangement changes when it emmits EM radiation
. electrons move closer to the nucleus
.they move to a lower energy level
how does the ratio of electrons to protons in an atom result in the atom having no overall charge
.the number of protons is equal to the number of electrons
. protons and electrons have equal and opposite charges, so charge cancels
what do all forms of the same element have in common
they all have the same number of protons
what is the name given to the number of protons in an atom
atomic number
what is an atoms mass number
the total number of nuetrons and protons in the atom
what is an isotope of an atom
an atom of an element that has a different number of nuetrons,but the same number of protons.
how do atoms turn into positive ions
.they lose one or more of their outer electrons
.electrons are negatively charged,so the resultant charge of the atom is positive
what may lead to a scientific model being changed or replaced
the discovery of new experimental evidence which doesent agree with the exisiting theory
how did the plum-pudding model describe the atom
a ball of positive charge, with negatively charged electrons distrubuted evenly throughout it
prior the discovery of the electron what was believed about the atom
the atom was believed to be indivinsible
which experiment led to the plum-pudding model being discarded
rutherfords, alpha-scattering experiment
what is the name given to the currently accepted model of the atom
the Bohr nucleur model
state the conclusions of the Alpha-scattering experiment
.most of the mass of the atom is concentrated at the centre in the nucleus
.the nucleus is positively charged
what rienforces a scientific theory
when experimental results agree with the hypothenised theortical calculations and theories
what did james chadwicks experiments on the atom prove
the existence of nuetrons
