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state the size and radius of an atom
very small
with a radius of 1 x 10-10
state the basic structue of an atom
a positively-charged nucleus
composed of both protons and neutrons
surrounded by negatively-charged electrons
state the size of the radius of a nucleus in comparison to the size of the atom
1:10,000
state where most of the mass in an atom is concentrated
nucleus
state how the electrons in an atom are arranged
at different distances from the nucleus
in shells
based on energy levels
with electrons closest to the nucleus having the lowest energy levels
state how the absorption of electromagnetic radiation affects the electronic configuration of electrons in an atom
electrons move further away from the nucleus
electrons gain energy
state how the emission of electromagnetic radiation affects the electronic configuration of electrons in an atom
electrons move closer to the nucleus
electrons lose energy
state the number of electrons in an atom in comparison to the number of protons
number of electrons is equal to the number of protons
state the electrical charge of an atom
atoms have no electrical charge
state whether or not the number of protons changes between atoms of the same element
the number of protons remains the SAME
state what the name for the number of protons in an atom is
atomic number
state what the name for the number of protons and neutrons in an atom is
mass number
state whether or not the number of neutrons changes between atoms of the same element
the number of neutrons can CHANGE
state the name of atoms of the same element that have a different number of neutrons
isotopes of the same element
state what happens if an atom loses outer electrons
it will become a positive ion (cation)
state what can cause the scientific model to change
new experimental evidence
state what atoms were thought to be before the discovery of electrons
tiny spheres
that cannot be divided
state which model the discovery of the electron created
plum pudding model
state what the plum pudding model suggested
the atom is a ball
of positive charge
with negative electrons embedded in it
state what the results from the alpha particle scattering experiment led to
the conclusion that the mass of an atom is concentrated in the nucleus
and that the nucleus was charged
explain how Niels Bohr adapted the nuclear model
Bohr suggested that electrons orbit the nucleus
at specific distances
state the name of particles with a positive charge
protons
state what the work of James Chadwick provided
evidence to show the existence of neutrons within the nucleus
state what the scattering experiment was
the scattering experiment was when a beam of alpha particles was directed through a gold foil
carried out by Ernest Rutherford, Hans Geiger and Ernest Marsden
explain what the new evidence from the scattering experiment was
when the beam of alpha particles was directed through the gold foil
researchers were expecting the particles to travel through the foil
and the beam to slightly change direction
however they discovered that most of the alpha particles passed through the foil
some of the alpha particles changed direction but continued through the foil
and a few of the alpha particles bounced off the foil
explain why the new evidence from the scattering experiment led to a change in the atomic model
the bouncing back of some of the alpha particles could not be explained by the plum pudding model
so a new model had to be created
explain the differences between the plum pudding model and the nuclear model
the plum pudding model is a positive sphere with negative charges embedded in it
there are no empty spaces
in the nuclear model, there is a central positive nucleus
with mostly empty space
and lots of negative charge varying distance from the nucleus
state what nuclear equations are used to represent
radioactive decay
state the representation of a beta particle in a nuclear equation
state the representation of an alpha particle in a nuclear equation
state what an alpha particle consists of
2 protons
2 neutrons
state the charge of an alpha particle
+2
state the charge of a beta particle
-1
state when a beta particle is produced
when a neutron changes into a proton and electron
state what a beta particle is
a fast-moving electron
state how an atom becomes more stable
by giving out radiation
state what the process of atom giving out radiation is
radioactive decay
state what activity is
the rate at which
a source
of unstable nuclei decays
state what activity is measured in
becquerel (Bq)
state what count rate is
the number of decays
recorded each second
by a detector (e.g. Geiger-Muller tube)
state what nuclear radiation may be emitted as
an alpha particle
a beta particle
a gamma ray
state whether alpha particles can penetrate through paper
no
state whether alpha particles can penetrate through aluminium
no
state whether alpha particles can penetrate through lead
no
state the ionising power of alpha particles
high
state the range of alpha particles in air
3-5cm
state whether
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