LESSON PLAN

1. SPECIFICATION OF THE SUBJECT LEARNT

Learning Subject : Chemistry

Topic Learnt : Atomic Structure

Grade/ Semester : X/ 1

Target Group : Those underlied by SETS vision and approach

Time Allocation : 6 x 45 menit

2. ACHIEVED COMPETENCY AND THE INDICATORS

Standar Competency:

To comprehend atomic structure, the periodical properties of the elements, and chemical

bond

Basic Competency:

To comprehend atomic structure based on atomic theory Bohr, element characters, relative

atomic mass, and periodic of element in periodic table and realize the regularity through

electron configuration understanding and the physical properties and chemical properties of

element with their implication in the SETS context

Indicators of competency achievement

To determine the elementary particles (proton, electron, and neutron)

To determine the electron configuration and valence electron

To determine the relative atomic mass based on periodic table

To classify the element into isotope, isobar, and isoton

To explain development of atomic theory to show weakness and superiority of each

atomic theory based on experiment data.

To describe structure of element periodic table

To compare the development of periodic table to identify their superiority and

weakness

To explain the basis of element grouping in the periodic table

To classify element into metal, non metal and metalloid

To analyze tables and graph to determine trends of atomic radius, ionization energy,

and electronegativity

To provide examples products of some element

To explain the implication of the chemical production toward environment, society, as

well as the technology applied.

3. LEARNING ACTIVITIES

a. Learning Approach: SETS Approach

b. Forms of Activities

1) First Meeting ( 2 x 45 minutes )

I. Introduction (5 minutes)

Pupils are asked to brainstorm on what is atom, and try to imagine atom

shape by description.

II. Main Activities (80 minutes)

Pupils gather in their group, bring their concept maps about the atomic

structure (as their assignment at last meeting), and exhibit the results of their

concept mapping on the wall near the group (3 minutes)

Each group should observe the concept maps produced by the other groups (7

minutes)

Pupils and teacher evaluate the concept map (10 minutes)

Teacher present the material on the 1st-4th indicators (40 minutes)

In group, students discuss about development of atomic theory to show

weakness and superiority of each atomic theory (10 minutes)

Students are presenting and discussing the result of study (10 minutes)

III. Closing the Class (5 minutes)

Teacher let pupils to ask some questions about the materials.

Pupils conclude result of study guided by teacher.

Pupils are given some homework about electron configuration.

2) Second Meeting ( 2 x 45 minutes )

I. Introduction (8 minutes)

Pupils are asked to brainstorm on periodic table, atomic radius, ionization

energy, electron affinity, and electronegativity.

II. Main Activities (75 minutes)

Pupils are asked to make the group in 4. (3 minutes)

Students are given an article about the development of periodic table (2

minutes)

In group, pupils discuss on the weakness and superiority of each periodic

table (10 minutes)

One pupil of each group are reading the result of group discussion (7

minutes)

Teacher gives the confirmation (8 minutes)

Teacher present the material on the basis of element grouping in periodic

table and classification of element into metal, non metal and metalloid (15

minutes)

Pupils are given the material about of atomic radius, ionization energy,

electron affinity, and electronegativity (1 minutes)

In group, pupils discuss cooperatively to study trends of atom radius,

ionization energy, electron affinity, and electronegativity of elements in

period and group based on data or graph and atomic number (14 minutes)

One pupil of each group are writing the result of group discussion (5

minutes)

Teacher gives the confirmation (10 minutes)

III. Closing the Class (7 minutes)

Teacher let pupils to ask some questions about the materials.

Pupils and teacher make the conclusion of the materials that have been

learned.

Pupils in group in 5 are assigned to make a paper about physical and

chemical properties of an element in environment and related with SETS

context. Each group must be discussing the different element.

For next meeting, each groups are also bring a sample of product that consist

of the element based on the paper. Paper will be present in presentation next

meeting.

3) Third Meeting ( 2 x 45 minutes )

I. Introduction (10 minutes)

Pupils are asked to brainstorm on classify example element in surrounding class

into metal, non metal and metalloid.

II. Main Activities (70 minutes)

Teacher describes about the properties some element in periodic table and

explain about the physical and chemical properties and their implication in

SETS context (10 minutes).

Pupils are asked to join with their group (8 groups) (3 minutes)

Teacher give work sheet there is blank concept map to each group. Each

group would be discuss to fill the work sheet based on the paper that

assigned at the last meeting about physical and chemical properties of an

element in environment and related with SETS context. (12 minutes).

By the agreement of all groups, three group asked to do presentation, one by

one of group and do discuss about the matter that learn in class guided by

teacher.

Teacher asks each group to evaluate the concept map of another group when

presentation and give comment on it. (15 minutes for each group, 45 minutes

for all).

III. Closing the Class (10 minutes)

Teacher will guide the pupils on concluding the course of activities following

the main course of the discussion.

Teacher asks pupils to collect the works of work sheet and the paper with

power point that presented.

4. INSTRUCTIONAL MATERIALS

Learning Materials:

Samples of real substances related to hydrocarbon available at home and the

surrounding of the students’ living compounds like diesel fuel, gasoline, kerosene,

candle, hard and soft paraffin,

Relevant printed materials or information downloaded from internet

References

Chemistry books containing information on atomic structure

• World of Chemistry Book

• LKS Kimia Kharisma SMA X semester 1

• Sains Kimia Book Kurikulum 2004 : 1A, publisher: Bumi Aksara

• Kimia Book for Senior High School: 1A, publisher: Yudhistira

Information on newspaper related to the hydrocarbon compounds, their implication to

the environment and the society in terms of the prices, the hazardous impact, as well as

the benefit of the compounds to the society.

Information in the internet relevant to the above matter.

5. LEARNING PRODUCTS

Human Resources

Pupils who understand the concepts learnt and their implication to the science and

technology progress as well as their implication to the environment and the society

Pupils who have some ideas on how to apply their knowledge for solving their daily life

problems.

Non Human Resources

Collection of information relevant to the understanding of the pupils on the concepts

learnt through concept maps

6. EVALUATION ON THE LEARNING PROGRAM

Program Evaluation

Adequacy and relevance of the planning, implementation, and the evaluation through self,

group, and process observation by the teacher and pupils.

Learning Evaluation

Cognitive aspect

Testing on the pupils understanding on the concepts of atomic structure, properties of

periodic table, and understanding psycal and cemichal properties of some element in

periodic table.

Understanding of concept maps (work sheet) to show the relation with SETS context.

Paper as assignment.

Affective Aspect

Observe the pupils’ expression and comments when they are shown with information and

other relevant the concepts of atomic structure, properties of periodic table, and

understanding psycal and cemichal properties of some element in periodic table.

Psychomotor Aspect

Observe the pupils’ capabilities in discussion, presentation and on handling materials on the

concepts of atomic structure, properties of periodic table, and understanding psycal and

cemichal properties of some element in periodic table.

ATTACHMENT :

1. WORK SHEET

2. LEARNING MATERIAL

A. Atomic Structure

SCIENE :

ENVIRONTMENT :

TECHNOLOGY : SOCIETY :

1) Internal Particle of atom

Atom consist of some particle:

1. Electron

Composer particle of atom that has mass 9.11×10-28

gram and has charge -1

2. Proton

Composer particle of atom that has mass 1,673×10-24

gram and has charge +1

3. Neutron

Composer particle of atom that has mass 1,675×10–24 gram and has neutral charge.

2) Atomic number and mass number

Atomic number is the number of protons in the nucleus of a given atom. And mass number

is the total number of protons and neutrons in the nucleus of a given atom.

Isotope

Isotope is atoms with the same number of protons but different numbers of

neutrons.

Example:12C6 proton = 6, neutron = 6 elektron = 613C6 proton = 6, neutron = 6, elektron =7

Isobar

Isobar is different atom but has the same mass number

Example : 24Na11 with 24Mg12 has same number 24.

Isoton

Isoton is different atom but has same number of neutron.

Example : 20Ca40 with 39K19

3) Electron Configuration

According to Bohr's atomic model, electrons around the nucleus in

certain paths called shells or energy levels. Shell that is occupied

electrons depends on energy. Lowest energy levels of atoms is the shell

located at least in or closest to the core, the more out of the greater number

shell and the greater the energy level.

To determine the electron configuration of an element, there are some

standards that must be kept in mind, namely:

a. Starting from the track closest to the core, each trajectory

referred to a shell-1 (K shell), shell-to-2 (L shell), shell-to-3 (shell M),

shell-to-4 (shell N), and so on.

b. The maximum number of electrons (at most) that can occupy

each shell is: 2 n2 , with n = number of shell

K shell can accommodate a maximum of 2 electrons.

L shell can accommodate a maximum of 8 electrons.

M leather can accommodate a maximum of 18 electrons, and so on.

c. The outer skin may only contain a maximum of 8 electrons.

B. Development Atomic Theory

1. Dalton’s Atomic Theory

1) Elements are made of tiny particles called atoms.

2) All atoms of a given element are identical.

3) The atoms of a given element are different from those of any other

element.

4) Atoms of one element can combine with atoms of other elements to form compounds. A

given compound always has the same relative numbers and types of atoms.

5) Atoms are indivisible in chemical processes. That is, atoms are not created or destroyed in

chemical reactions. A chemical reaction simply changes the way the atoms are grouped

together.

2. J.J Thomson’s Atomic Theory

The Plum Pudding Model

Given J. J. Thomson’s results, it was natural to wonder what the atom might look like. J. J.

Thomson and William Thomson (better known as Lord

Kelvin, and no relation to J. J.) are credited with proposing that

the atom might be something like plum pudding (a pudding with

raisins randomly distributed throughout). They reasoned that the

atom might be thought of as a uniform “pudding” of Figure 1.2

Figure 1.1

positive charge with enough negative electrons scattered within to counterbalance that positive

charge (see Figure 1.2). Thus the plum pudding model of the atom came into being.

3. Rutherford’s Atomic Theory

Ernest Rutherford revealed that the Atom is described as an empty room

with a core containing a positive charge located in the center and the

electrons orbit around the nucleus. (see Figure 1.3).

4. Bohr’s Atomic Theory

Bohr said that the electrons surrounding the atomic nucleus at certain

energy levels (electron shells) and the electrons can move from one

energy level to another energy by releasing or absorbing energy.

(see Figure 1.4).

B. Development of Periodic Table

Because of the importance of the outermost electron shell, the different regions of the periodic table

are sometimes referred to as periodic table blocks, named according to the subshell in which the

"last" electron resides. The s-block comprises the first two groups (alkali metals and alkaline earth

metals) as well as hydrogen and helium. The p-block comprises the last six groups which are

groups 13 through 18 in IUPAC (3A through 8A in American) and contains, among others, all of

the metalloids. The d-block comprises groups 3 through 12 in IUPAC (or 3B through 8B in

American group numbering) and contains all of the transition metals. The f-block, usually offset

below the rest of the periodic table, comprises the lanthanides and actinides

Figure 1.4

Figure 1.3

Periods (periodic table)

A period is a horizontal row in the periodic table. Although groups are the most common way of

classifying elements, there are regions where horizontal trends are more significant than vertical

group trends, such as the f-block, where the lanthanides and actinides form two substantial

horizontal series of elements.

1. Dobereiner’s Law of Triads

The development of the periodic table begins with German chemist Johann

Dobereiner (1780-1849) who grouped elements based on similarities.  Calcium (atomic

weight 40), strontium (atomic weight 88), and barium (atomic weight 137) possess similar

chemical prepares.  Dobereiner noticed the atomic weight of strontium fell midway between

the weights of calcium and barium:

Ca  Sr   Ba     (40 + 137) ÷ 2 = 88

40     88     137

Dobereiner  noticed the same pattern for the alkali metal triad (Li/Na/K) and the

halogen triad (Cl/Br/I)

Li   Na  K         Cl   Br   I

7     23     39           35    80   127

In 1829 Dobereiner proposed the Law of Triads: Middle element in the triad had

atomic weight that was the average of the other two members.

The weakness of this theory is:

a. The grouping of elements is less efficient in the presence of several other elements

and are not included in the triad when the same nature with the elements of the triad

group

b. A lot of elements that have similar properties but there are more than three.

c. There was not a lot of triads which are found.

The superiority of this theory is:

a. The order of elements that have similar characteristic.

b. The calculation of the triads, there are almost close to the mass of atoms in the

periodic table that we now use.

2. Law of Octaves ( based on increasing atomic weights)

English chemist John Newlands (1837-1898), having arranged

the 62 known elements in order of increasing atomic weights,

noted that after interval of eight elements similar

physical/chemical properties reappeared. 

The weakness of the theory : only used for light elements or to

elements with maximal atomic mass is 40.

The superiority of the theory : 1 octave disputing elements

indicate the similarity of properties.

3. Mendeleev's Periodic Table (increasing relative atomic weights)

Then in 1869, Russian chemist Dimitri Mendeleev (1834-

1907) proposed arranging elements by atomic weights and

properties (Lothar Meyer independently reached similar

conclusion but published results after Mendeleev). 

Mendeleev's periodic table of 1869 contained 17 columns with

two partial periods of seven elements each (Li-F & Na-Cl)

followed by two nearly complete periods (K-Br & Rb-I).

The weakness of this theory :

a. Still contained elements of a larger mass is located in front of the element whose

mass is smaller. Co: Tellurium (te) = 128 in the left-iodine (I) = 127. This is because

the elements that have a similarity of nature is placed in one class.

b. there is an element of atomic mass increase is not appropriate because it is closer to

the similarity of properties.

The superiority of this theory:

a. The justification of the atomic mass. Before, atomic mass In = 76 become 113.

Moreover Be = 13.5 become 9. U = 120 become 240.

b. Mendeleev’s periodic table was also predict undiscovered elements and predicted

the mass of the atoms of the element..

4. Noble Gases

Lord Rayleigh (1842-1919) and William Ramsey (1852-

1916) greatly enhanced the periodic table by  discovering the "inert

gases."  In 1895 Rayleigh reported the discovery of a new gaseous

element named argon. This element was chemically inert and did not

fit any of the known periodic groups. Ramsey followed by discovering the remainder of the

inert gases and positioning them in the periodic table. So by 1900, the periodic table was

taking shape with elements were arranged by atomic weight.  For example, 16g oxygen

reacts with 40g calcium, 88g strontium, or 137g barium. If oxygen used as the reference,

then Ca/Sr/Ba assigned atomic weights of 40, 88, and 137 respectively.

Rayleigh (physics) and Ramsey (chemistry) were awarded Nobel prizes in 1904. 

The first inert gas compound was made in 1962 (xenon tetrafluoride) and numerous

compounds have followed (see xenon compounds)--today the group is more appropriately

called the noble gases.

4. Moseley's Periodic Law (based on increasing proton number/ atomic number)

Soon after Rutherford's landmark experiment of discovering the proton in 1911,

Henry Moseley (1887-1915) subjected known elements to x-rays. He was able to derive the

relationship between x-ray frequency and number of protons. When Moseley arranged the

elements according to increasing atomic numbers and not atomic masses, some of the

inconsistencies associated with Mendeleev's table were eliminated. The modern periodic

table is based on Moseley's Periodic Law (atomic numbers). At age 28, Moseley was killed

in action during World War I and as a direct result Britain adopted the policy of exempting

scientists from fighting in wars.  Shown below is a periodic table from 1930:

The weakness of the theory : there is an element that is not similar to the nature of the

bottom, example: H.

The superiority of the theory : increase in the relative atomic mass of an element is

in conformity with the increase in atomic number.

Properties of Periodic table

tal, non metal and metalloid

Most elements are metals. They are usually shiny, very dense, and only melt at high

temperatures. Their shape can be easily changed into thin wires or sheets without

breaking. Metals will corrode, gradually wearing away, like rusting iron. Heat and

electricity travel easily through metals, which is why it is not wise to stand next to a

flagpole during a thunderstorm!

Nonmetals, on the right side of the periodic table, are very different from metals. Their

surface is dull and they don’t conduct heat and electricity. As compared to metals, they

have low density and will melt at low temperatures. The shape of nonmetals cannot be

changed easily because they are brittle and will break.

Elements that have properties of both metals and nonmetals are called metalloids. They

can be shiny or dull and their shape is easily changed. Electricity and heat can travel

through metalloids but not as easily as they travel through metals.

4) Atomic Radius, Ionization energy, Electronegativity

Atomic Radius

The atomic radius of an element is half of the distance between the centers of

two atoms of that element that are just touching each other. Generally, the atomic

radius decreases across a period from left to right and increases down a given group.

The atoms with the largest atomic radii are located in Group I and at the bottom of

groups.

Moving from left to right across a period, electrons are added one at a time to

the outer energy shell. Electrons within a shell cannot shield each other from the

attraction to protons. Since the number of protons is also increasing, the effective

nuclear charge increases across a period. This causes the atomic radius to decrease.

Moving down a group in the periodic table, the number of electrons and filled

electron shells increases, but the number of valence electrons remains the same. The

outermost electrons in a group are exposed to the same effective nuclear charge, but

electrons are found farther from the nucleus as the number of filled energy shells

increases. Therefore, the atomic radii increase.

Ionization Energy

The ionization energy, or ionization potential, is the energy required to

completely remove an electron from a gaseous atom or ion. The closer and more

tightly bound an electron is to the nucleus, the more difficult it will be to remove,

and the higher its ionization energy will be. The first ionization energy is the energy

required to remove one electron from the parent atom. The second ionization energy

is the energy required to remove a second valence electron from the univalent ion to

form the divalent ion, and so on. Successive ionization energies increase. The second

ionization energy is always greater than the first ionization energy. Ionization

energies increase moving from left to right across a period (decreasing atomic

radius). Ionization energy decreases moving down a group (increasing atomic

radius). Group I elements have low ionization energies because the loss of an

electron forms a stable octet.

Electronegativity

Electronegativity is a measure of the attraction of an atom for the electrons in

a chemical bond. The higher the electronegativity of an atom, the greater its

attraction for bonding electrons. Electronegativity is related to ionization energy.

Electrons with low ionization energies have low electronegativities because their

nuclei do not exert a strong attractive force on electrons. Elements with high

ionization energies have high electronegativities due to the strong pull exerted on

electrons by the nucleus. In a group, the electronegativity decreases as atomic

number increases, as a result of increased distance between the valence electron and

nucleus (greater atomic radius). An example of an electropositive (i.e., low

electronegativity) element is cesium; an example of a highly electronegative element

is fluorine.

C. Physical property and Chemical property

Physical property is characteristic of a substance that can change without the substance's

becoming a different substance. Characteristics are examples of physical properties. Substances

also have physical properties. The typical physical properties of a substance include odor, color,

volume, state (gas, liquid, or solid), density, melting point, and boiling point.

Chemical property is characteristic that describes the ability of a substance to change to a

different substance. An example of a chemical change is wood burning in a fireplace, giving off

heat and gases and leaving a residue of ashes. In this process, the wood is changed to several new

substances. Other examples of chemical changes include the rusting of steel, the digestion of food,

and the growth of plants. In a chemical change a given substance changes to a fundamentally

different substance or substances.

A physical change involves a change in one or more physical properties, but no change in

the fundamental components that make up the substance. The most common physical changes are

changes of state: Solid - liquid - gas

A chemical change involves a change in the fundamental components of the substance; a

given substance changes into a different substance or substances. Chemical changes are called

reactions: silver tarnishes by reacting with substances in the air; a plant forms a leaf by combining

various substances from the air and soil; and so on.