WorksheetsBohr & Chadwick
Total questions: 21
Worksheet time: 11mins
According to our physics knowledge, an object moving on a circular path
has a constant velocity
has an acceleration
can never stop
is acted upon by a net force equal to zero
According to our physics knowledge, when a charge is accelerated
it must radiate energy
it is going to move too fast
it must absorb energy
it must decelerate
If the electron radiates energy while it is moving around the nucleus, it will eventually
leave the nucleus
become positive
stop its motion
fall on the nucleus
According to Bohr's first postulate,
In each atom there are only a discrete number of orbits allowed
in each atom electrons can move freely
in each atom there is a different number of electrons
all the atoms are neutral
According to Bohr's second postulate,
electrons in the atoms stay still
electrons moving along the allowed orbits do not radiate energy
the atom is a small planetary system
electrons moving along the allowed orbits radiate energy
There is a very important difference between the solar system and the structure of the atoms:
in the solar system an object can move around the sun at every possible distance from the sun while in the atoms only certain orbits are permitted
the planets are much bigger than the electrons
the planets aren't charged
there isn't any important difference
The electron orbitals are called
ellypses
circles
shells
roads
The inner shells in an atom are called
A, B, C, D
Y, W, X, Z
α, β, γ, δ
K, L, M, N
In Bohr's model there was a missing particle
the quark
the neutron
the proton
the neutrino
Chadwick discoverd the neutron in
1932
1905
1897
1913
one important clue that lead Chadwick to his discovery was that the protons in the nucleus should
attract each other
repel each other
move
exit the nucleus
1 amu is
a unit of mass equal to the mass of a proton
a unit of mass equal to the mass of an electron
a unit of distance, equal to the distance travelled by the light in 1 s
a unit of charge equal to the charge of the electron
Another clue that lead Chatdwick to his discovery was that
the mass of an helium nucleus seemd to be smaller that the mass of thu hydrogen nuclei
all the atoms are composed of protons, neutrons and electrons
you can simply add two hydrogen atoms to form an helium atom
the mass of an helium nucleus seemd to be larger that the mass of thu hydrogen nuclei
How many hydrogen atoms are necessary to balance the mass of one helium atom
1
2
3
4
Comparing the number of protons and atomic masses of several different atoms, scientist understood that
there is another kind of particle in the nucleus that add mass to it
there is another kind of particle in the nucleus that add charge to it
the unit of mass that they were using was wrong
atoms cannot be compared to one another
In his experiment Chadwick shot alfa particles on a beryllium or lithyum or boron sample and noticed that
canal rays came out of the sample
cathode rays came out of the samples
the samples became positively charged
there was some kind of radiation coming out of the sample
when Chadwick shot alfa particles on a beryllium or lithyum or boron sample the radiation coming out of these samples
was charged
wasn't charged
was green
were cathode rays
Chadwick used parafin that is a material similar to
gold
boron
water
wax
when the rays coming out of the beryllium or boron or lithyium samples hit the parafin
fast protons came out of it
slow protons came out of it
fast electrons came out of it
slow neutrons came out of it
Chadwick understood that the ray coming out of the beryllium or boron or lithyium samples were composed of particles
with the same charge of the protons
with the same charge of the electrons
with the same mass of the protons
with the same mass of the electrons
a pool ball is
a bowling ball
a football ball
a billiard ball
a tennis ball
