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P2.5.1 Atomic structure
P2 Physics
Mr D Powell
Connection
•
•
•
Connect your learning to the
content of the lesson
Share the process by which the
learning will actually take place
Explore the outcomes of the
learning, emphasising why this will
be beneficial for the learner
Demonstration
• Use formative feedback – Assessment for
Learning
• Vary the groupings within the classroom
for the purpose of learning – individual;
pair; group/team; friendship; teacher
selected; single sex; mixed sex
• Offer different ways for the students to
demonstrate their understanding
• Allow the students to “show off” their
learning
Activation
Consolidation
• Construct problem-solving
challenges for the students
• Use a multi-sensory approach – VAK
• Promote a language of learning to
enable the students to talk about
their progress or obstacles to it
• Learning as an active process, so the
students aren’t passive receptors
• Structure active reflection on the lesson
content and the process of learning
• Seek transfer between “subjects”
• Review the learning from this lesson and
preview the learning for the next
• Promote ways in which the students will
remember
• A “news broadcast” approach to learning
Mr Powell 2012
Index
P2.5.1 Atomic Structure
a)
The basic structure of an atom is a small central nucleus composed of protons
and neutrons surrounded by electrons. (Rutherford Model)
b)
The relative masses and relative electric charges of protons, neutrons and
electrons.
c)
In an atom the number of electrons is equal to the number of protons in the
nucleus. The atom has no overall electrical charge.
d)
Atoms may lose or gain electrons to form charged particles called ions.
e)
The atoms of an element always have the same number of protons, but have
a different number of neutrons for each isotope. The total number of protons
in an atom is called its atomic number. The total number of protons and
neutrons in an atom is called its mass number.
Additional: Candidates should appreciate the relative size of the nucleus
compared to the size of the atom.
Mr Powell 2012
Index
a) Atomic Model
We used to think that atoms
weren't made up of smaller
pieces. The word "atom"
actually comes from a Greek
word which means "can't be
split up".
Now we know that all atoms are
actually made of the same 3 tiny
particles; protons, electrons and
neutrons.
The protons are positive and the
electrons are negative. Neutrons
are neutral.
Protons and neutrons are much
heavier than electrons and they
are found in the middle of the
atom called the nucleus. The
electrons are in orbit around the
Index
outside. Mr Powell 2012
a) & c Atomic Rules - recap
 The number of electrons is the same as the
number of protons
 The number of neutrons is usually about the
same as the number of protons though bigger
atoms tend to have more neutrons than
protons
Z = number of protons or
atomic number or
proton number
A = Atomic mass number
Z-A = number of neutrons
 Atoms have no overall charge.
 What are the protons, neutrons, electrons for
these three atoms…
3p, 4n, 3e
6p, 6n, 6e
79p, 118n, 79e
Mr Powell 2012
Index
a) Atomic Model Recap
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
Charge
Neutral
Electrons
Protons
Protons
Nucleus
Atomic
Proton
Nucleons
Nucleus
Mass
Atomic Mass
Word BANK
Write a-l in your book and
write in the correct order
for the words.
B – don’t use the word bank
C-E - Use the word bank to
help you
Nucleus, Mass, Protons,
Charge, Proton
,Nucleons, Atomic,
Atomic Mass,
Protons, Nucleus,
Neutral, Electrons
Mr Powell 2012
Index
d) Formation of Ions
When an electron is removed from an atom the overall charge will increase by +1
as an electron is -1 charged
When an electron is added to an atom the overall charge will decrease by -1 as an
electron is -1 charged
This example shows the formation of a simple ionic crystal, sodium chloride.
A Chlorine atom steals one from a sodium, forming ions and an attraction strong
enough to bond them together.
Mr Powell 2012
Index
a) Rutherford Scattering
In the early part of the last century, the
accepted model of the atom was
proposed by J J Thompson in his plum
pudding model. This consisted of a
matrix of protons in which were
embedded electrons.
Ernest Rutherford (1871 – 1937) used
alpha particles to study the nature of
atomic structure with the following
apparatus:
Rutherford was using alpha particles
(helium nuclei) as nuclear bullets to
smash up the atoms; he wanted to see
atoms bursting like watermelons. But…
His observations are best illustrated with
this video, animation and diagram....
Mr Powell 2012
Index
a) Rutherford Scattering - conclusions
Instead of bits of atom, Rutherford found that a small proportion of the alpha
particles were deflected, while an even smaller proportion bounced right back.
From analysis of these observations he concluded:




Most of the atom was empty space.
The positive charge was concentrated in a very small space
The radius of the nucleus was in the order of 3 × 10-14 m.
The alpha particles that were deflected back had to be travelling in a line with
the nucleus.
Rutherford’s estimates were not far out. Later research has shown the nuclear
radius to be in the order of 1.5 × 10-14 m. However the boundary is not sharp, but
rather fuzzy, as the nucleus is a very dynamic entity.
Mr Powell 2012
Index
a) Extended Creative Work!
Imagine that you are team of scientists (3-4) like Ernest Rutherford (1871 - 1937) who
have conducted the experiments that we have already talked about.
Produce a short talk of about (1 minute) about the topic which is designed to convince a
public in the year 1905 which at that time knew nothing about atoms part from that the
universe was made of them. You will have to present it to the rest of the group. Try and
speak about;
1) Atoms in general in simple terms. (C)
2) Atoms with specific reference to the electrons, neutrons & protons. (B/C)
3) Ideas of Isotopes. (Y10 work) (B/C)
4) The experiments you conducted (A-C)
5) Main results of your experiments (A*-C)
Mr Powell 2012
Index
Check - Multichoice....
Mr Powell 2012
Index
Summary Points…..
 The positive charge was
concentrated in a very small
space
 Most of the atom
was empty space.
 The alpha particles that were
deflected back had to be
travelling in a line with the
nucleus.
 The radius of the nucleus
was in the order of 3 × 10-14
m. (or very small compared
to atom size)
Mr Powell 2012
Index
P2.5.1 Atomic Structure
P2.5.1 Atomic Structure
P2.5.1 Atomic Structure
a)
The basic structure of an atom is a
small central nucleus composed of
protons and neutrons surrounded
by electrons. (Rutherford Model)
a)
The basic structure of an atom is a
small central nucleus composed of
protons and neutrons surrounded
by electrons. (Rutherford Model)
a)
The basic structure of an atom is a
small central nucleus composed of
protons and neutrons surrounded
by electrons. (Rutherford Model)
b)
The relative masses and relative
electric charges of protons,
neutrons and electrons.
b)
The relative masses and relative
electric charges of protons,
neutrons and electrons.
b)
The relative masses and relative
electric charges of protons,
neutrons and electrons.
c)
In an atom the number of
electrons is equal to the number
of protons in the nucleus. The
atom has no overall electrical
charge.
c)
In an atom the number of
electrons is equal to the number
of protons in the nucleus. The
atom has no overall electrical
charge.
c)
In an atom the number of
electrons is equal to the number
of protons in the nucleus. The
atom has no overall electrical
charge.
d)
Atoms may lose or gain electrons
to form charged particles called
ions.
d)
Atoms may lose or gain electrons
to form charged particles called
ions.
d)
Atoms may lose or gain electrons
to form charged particles called
ions.
e)
The atoms of an element always
have the same number of protons,
but have a different number of
neutrons for each isotope. The
total number of protons in an
atom is called its atomic number.
The total number of protons and
neutrons in an atom is called its
mass number.
e)
The atoms of an element always
have the same number of protons,
but have a different number of
neutrons for each isotope. The
total number of protons in an
atom is called its atomic number.
The total number of protons and
neutrons in an atom is called its
mass number.
e)
The atoms of an element always
have the same number of protons,
but have a different number of
neutrons for each isotope. The
total number of protons in an
atom is called its atomic number.
The total number of protons and
neutrons in an atom is called its
mass number.
Additional: Candidates should appreciate
the relative size of the nucleus compared
to the size of the atom.
Additional: Candidates should appreciate
the relative size of the nucleus compared
to the size of the atom.
Additional: Candidates should appreciate
the relative size of the nucleus compared
to the size of the atom.