Atomic structure Flashcards
who came up with the first development of atomic models and what did he say?
dalton
-said atoms were solid, tiny spheres
-they were indivisible
-different spheres represented deifferent elements
who came up with electrons and what did they say
jj thompson
-he said that atoms were not solid
-he came up with the plum pudding modelβ>said that atoms were a ball of positive charge with negative electrons embedded in it
who discovered the nucleus and what did they say?
rutherford
-said that nucleus was very small
-nucleus was positively charged(had protons)
-atom was mainly made of empty
-this empty spcae was a cloud of negative charge
-different elements have a different number of protons
what did it mean if nuclei was heavier than usual and what was discovered?
rutherford said that there was mass but no charge in the nucleus which then led to the discovery of neutron by chadwick.
what experiment did rutherfood conduct+why
gold leaf experimentβ>prove jj Thompson wrong
-alohas positive particles were shot through a thin sheet of gold
-most particles had gone through which proved that atom is made of empty spce
-some deflected which proved that atoms contained a small dense nucleus.
who discovered a problem with the rutherfords exp and what did he doscover?
bohr
he said that surely the clouds of negative electron would fall into the postive nucleus
-electrons only exist in fixed orbits or shells
-discovered there must be fixed energy shells
-fixed energy shells means a fixed frequency
-when electromagnetic energy is emmited or absorbed these ,ove up or down shells.
what experiment did bohr conduct?
-conducted the experimental proof
-had suggested that different shells have different levels of energy
-em radiation being absorbed means that energy levles move up
-em radiation being emmited means it moves to lower shells
how is the modern model like?
each shell has sub shells which explains ionisation trends
how are elements formed?
through nuclear fusion reactions
what is nuclear fusion?
fusion of two lighter nuclei to form a heavier nuclei which is a new element
what are the requirements for these nuclear fusion reactions + why?
-high temperature
-high pressure
to overcome repulsive force between the two positive nuclei
due the conditions of nuclear fusion where are they most common and provide an example
-most common in the sun
eg. isotopes of hydrogen to form helium
how many electrons can each shell hold
one-2
two-8
three-16
four-32
what are shells split up into and name them ?
subshells-s,p,d,f
how many orbitals are there in each subshell?
s-1
p-3
d-5
f-7
