Download LESSON PLAN School : State Senior High School ……………… The

LESSON PLAN
School
: State Senior High School ………………
The Lesson
: Chemistry
Subject
: Atomic Structure
Grade/ semester
: X/ 1
Time Allocation
: 2×45 minutes
Standard of Competence
:
Understanding atomic structure, the periodical properties of elements, and chemical
bonding.
Basic Competency
:
Understanding the structure based Bohr’s atomic model, element’s properties, relative
atomic masses, and the periodical properties of elements, also realizing its regularity by
understanding the electron configuration.
Teaching Objectives

:
Students are able to explain the discovery and development of atomic structure,
from Dalton atomic theory to modern atomic theory.

Students are able to determine the atomic structure based of atomic number and the
number atomic masses.

Students are able to categorize the element into isotope, isobar, and isoton based of
atomic number and the number atomic masses.
Indicator

:
Students are able to explain the development of atomic theory and model from
Dalton atomic theory to modern atomic theory.

Students are able to explain the atomic structure based of discovery that construct
the development of atomic theory and model from Dalton atomic theory to modern
atomic theory.

Students are able to explain the atomic structure based of discovery that construct
the development of atomic theory and model from Dalton atomic theory to modern
atomic theory.

Students are able to determine the basic particles (protons, electrons and neutrons)

Students are able to determine the atomic structure based of atomic number and the
number atomic masses.

Students are able to categorize the element into isotope, isobar, and isoton based of
atomic number and the number atomic masses.
Teaching Method
:

Lecturing

Giving Worksheet

Question Answer Methode
Media components
:
Notebook, LCD, Whiteboard, and Worksheet
Learning materials
:
Since the ancient Greek until present, atomic theory and model has been
developing. By this mean, we can discover the structure of atom. The progress is
worked by great scientists, such as Democritus, John Dalton, JJ Thompson, Rutherford,
Chadwick, Millikan, Niels Bohr, Schrodinger, de Broglie, and Heisenberg. From those
we can determine the atomic structure categorize the element into isotope, isobar, and
isoton based of atomic number and the number atomic masses.
Dalton atomic theory and model
Dalton proposed the first modern atomic theory that all matter is made of tiny
particles called atoms. According to Dalton’s atomic theory, atoms are solid particles
which are indivisible. So, based on Dalton’s atomic theory, atom can be drawn as
If there is atom X combine with atom Y, it’s product XY molecule. According to
Dalton’s atomic theory, the scheme of reaction is
+
X
+
Y
XY
So, the conclusion is atom can be combined in definite, fixed proportions to make
compounds.
JJ Thompson atomic theory and model
In Thompson’s experiment, he was using a glass tube called cathode ray tube. The
figure of cathode ray tube can illustrated bellow:
Figure 1. Cathode Ray Tube
1.
The experiment by JJ Thompson
Within the experiment, when the tube was connected to a source of electrical
energy and Thompson placed the electric field, the cathode light was attracted by
positive plate, but repelled by negative plate ( look the figure 1.) and when he
placed magnetic field on the beam pathway, Thompson showed that a positive side
of magnet made the cathode ray bend towards and the opposite happened when he
used a negative side of magnet (from the video). That’s mean the cathode ray had to
be made of negatively charged particle that called electron.
2.
Thompson’s atomic theory and model
This surprised Thompson, because the atoms of the gas were uncharged. Where
had the negative charged come from?
Thompson conclude that the negative charges came from within the atom). Since
the gas was known to be neutral, having no charge, he reasoned that there must be
positively charged particle in the atom.
So the atomic theory by JJ Thompson is the atom contained negatively charged
particle mixed evenly into a positively charged sphere. The negative and positive
charged cancelled each other out, so that atoms would have no charged if complete.
The figure of Thompson’s atomic model is
Rutherford atomic theory and model
From Rutherford’s experiment, got some data:
Alpha particles are positively charged, struck the sheet of gold foil.
The sheet of gold foil contains gold atoms.
97,99% alpha particles are transmitted. 2% alpha particles are diverted.
0,01% alpha particles are reflected.
Most of alpha particles are transmitted because they encounter the free space in the
gold atoms; therefore, most space of atom is free space. Meanwhile, the alpha particles
diverted are those touching the nucleus which is a big size and the ones reflected are
alpha particles which accurately collide with the nucleus and undergo repulsion force
because the mass atomic nucleus is positively charge.
Conclusion:
a. An atom consists of an atomic nucleus which is positively charged. The nucleus of
atom contains almost entire mass of the atom and is surrounded by electrons
which are negatively charged as in the solar system model.
b. Entirely, an atom is neutral because the number of its positive charges (protons) is
equal to that of its negative charges.
c. During revolving the nucleus, the centripetal force on electrons in an atom is
produced by the force of attraction between the electrons and nucleus (Coulomb
force).
Niels Bohr atomic theory and model
Niels Bohr completed Rutherford theory by placing the quantum theory of Plank
and Einstein in it. According to Bohr, the electron motion around the nucleus must
progress in certain angle momentum.
Every energy level will be filled by certain amount of electron. According to Bohr,
the maximum electron in every level was 2n2.
Letters K, L, M, and so on declared as electron orbital in every level. Level 1 (n = 1)
called orbital K, n = 2 called orbital L, and so on. The electron, which falls from low
energy to upper level, will cause energy absorption and produce discreet color.
The Bohr’s atomic model is:
In brief, the theory mention by Bohr can be comprehended as follow:
1. Electrons are moving around nucleus in discreet level of energy.
2. Electron may transfer from one energy level to another energy level.
a. From low energy to upper level is called excitation, and it absorbs energy.
b. From high energy to lower level is called de-excitation, and it release
energy.
 Proton is positively charged particle which was discovered by Eugene Goldstein
by continuation rays experiment.
 J. Chadwick discovered neutron from the shooting of beryllium using alpha
particles and then this neutron known as the particle composing the atom
nucleus.
 Neutron is uncharged particles.
Symbol of Atom
X = the name/symbol of atom
A = mass number of atom = number of protons + number of neutrons
Z = atomic number = number of protons = number of electron
 Isotope is one of two or more species of an element that have the same atomic
number, but different mass number.
 Isobar is atom which come from different element but they have same mass number
 Isoton is atom which come from different element but they have same number of
neutrons.
Teaching and Learning Objectives
Opening ( 5 minutes)
No. Activities
Teacher’s Language
1.
Greeting
Good morning, class.
2.
Asking for student’s condition
How are you today?
3.
Leading a prayer
Before we start our lesson today, let’s pray
together. Prayer, do. … Thank you.
4.
Checking attendance
Who is absent today?
5.
Apperception
Have the relation with our lesson today we will
talk about chemistry. You know that almost of
the “things” in our world has the relation with
chemistry (give example). And this things
begin from the smaller particle that construct
this ”things”. Begin from this. “the calk”. What
do you think when we broken into 2 parts?
And when we grind until become the powder
and it can’t grind anymore or we can called it
the matter could not be divided into smaller
and smaller pieces forever. You know what is
it? Yes you right its called atom. And this
theory based of
Democritus. Now we will
study about the discovery and development of
atomic structure, from Dalton atomic theory to
modern atomic theory.
Core activities ( 80 minutes)
Teacher’s Language
No. Activities
Exploration
1.
OK. Look at the slide. We begin from Dalton
Teacher explains about the atomic theory to modern atomic theory.
discovery and development of
atomic structure, from Dalton
atomic
theory
to
modern
atomic theory.
Giving task to student.
OK. From my explanation I want you to make
resume about the discovery and development
of atomic structure, from Dalton atomic theory
to modern atomic theory in your book. And
you can follow the format like in the slide. And
the next time I will check your work.
Continue the explanation about Come back to the matter. The one atomic
the atomic structure.
structure with the other has the different in the
number of proton, electron, and neutron. OK
we will study about it. (study about atomic
number and the number atomic masses and
isotope, isobar, and isoton)
2.
Elaboration
Giving the exercise
I have the exercise to you. Please do it. I give
you 15 minutes to do it and I want one of you
share your answer to the class.
3.
Confirmation
Explaining the right answer
Teacher Explains answer the problem of
practice which have been done student
Closing ( 5 minutes)
No. Activities
Teacher’s Language
1.
That’s all the time we have for today. Please,
Propose the next topic
read
the
next
matter
about
electron
configuration and relative atomic masses.
Don’t forget the task.
2.
Leave Taking
See you later.
Learning Source
Justiana, Sandri and Muchtaridi. 2009. Chemistry for Senior High School 1 Year X.
Jakarta: Yudhistira.
Purba, Michael. 2007. Kimia untuk SMA Kelas X Semester 1. Jakarta: Penerbit
Erlangga.
Sunardi. 2007. Kimia Bilingual Untuk SMA/ MA Kelas X Semester 1 dan 2. Jakarta:
Yrama Widya.
Tim Penyusun. 2010. Kreatif Kimia untuk SMA/ MA Kelas X Semester Gasal. Klaten:
Viva Pakarindo.
Assessment
Cognitive
:
: The result of student Exercise
Psycomotoric (enclosure)
Affective
: Attendance
Approved by
Yogyakarta, ……… 2012
Prinsiple
Subject Teacher
Reskunanda Adhi W
Evaluation
The Discovery and Development of Atomic Structure
Event
Result
Excess
Weakness
Person
Experiment
involved
Democritus
…
…
…
…
Dalton
…
…
…
…
JJ Thompson
…
…
…
…
Rutherford
…
…
…
…
Niels Bohr
…
…
…
…
…
…
Discovery of
…
…
…
…
Proton
…
…
Discovery of
Neutron
Exercise
1. Determine the number of protons, electrons and neutrons of the following atoms
a.
b.
c.
d.
e.
2. Classify the following atoms into isotope, isobar and isoton
,
,
,
,
,
Answer
1. the number of protons, electrons and neutrons of the following atoms
a.
, number of protons: 6
number of electrons :6
number of neutrons : 6
b.
number of protons: 11
number of electrons : 11
number of neutrons : 12
c.
number of protons: 47
number of electrons :47
number of neutrons : 61
d.
number of protons: 55
number of electrons :55
number of neutrons : 78
e.
number of protons: 83
number of electrons :83
number of neutrons : 126
2. Classify the following atoms into isotope, isobar and isoton.
Isotope
:
and
and
Isobar
:
and
Isoton
:
,
, and
Psycomotoric
Perception sheet of students
No
Name
Assessment scale:
1
: Very less
2
: Less
3
: Enough
4
: Good
5
: Very good
Participation
Having a
notion
Asking
Correct
reactions
Average