Atoms and Molecules


Lesson Plan of Introduction to Atoms and Molecules

General Science Grade VI

Students’ Learning Outcomes

·         Different between an atom and a molecule.
·         Recognize the symbols of some common elements.
·         Differentiate between elements, compounds and mixtures.
·         Identify examples of some compounds and mixtures from their surroundings.

Information for Teachers

Concept Map

·         Matter is anything that takes up space and has mass.
·         All matter is made of atoms.
·         Atoms are the building blocks of matter. Kinds of how bricks of the building blocks of the houses.
·         Atom:  The basic unit of a chemical element.
·         Atom: An extremely small amount of a thing or quality.
·         Atoms are composed of particles called protons, electrons and neutrons
·         An element is a pure chemical substance which contains same type of atoms.
·         A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. Molecules are made up of atom s that are held together by chemical bonds. These bonds form as a result of the sharing or exchange of electron s among atoms
Atoms and Molecules
·         A symbol is a letter used to represent something.
·         Chemists use symbols to represent elements. Chemists use one or two letters to represent elements.
·         The symbol for aluminum is Al.
·         The symbol for oxygen is O.
·         A compound is a substance formed when two or more elements are chemically joined.
·         Water, salt, and sugar are examples of compounds.
·         When the elements are joined, the atoms lose their individual properties and have different properties from the elements they are composed of.
·         A chemical formula is used as a quick way to show the composition of compounds.
·         Molecules of element have same kind of atoms while molecules of compound have different kind of atoms.
·         A mixture is made up of two or more different substances which are mixed together but are not chemically combined.

Material / Resources

Paper clips (12 of each color i.e. green, red and yellow), sulfur powder, iron fillings, china dish, burner/spirit lamp, bar magnet

Worm up activity

·         Write the word “Atom” on board and ask students to tell what they know about an “Atom”
·         Write their answer on board and give a brief touch to each answer.

Introductory Activity

·         Draw equal sized small circles as shown below in the box- a on board.
·         Draw circles larger in size than those of box- A as shown in the box – B on board.
·         Each circle represents an atom.
·         
·         Ask students to observe/see the circles and answer the following questions.
       
o   Can we represent atoms by small circles?
o   Are these circles of the same size of both boxes?
(Tell the students that atoms of the same size and shape form a pure substance known as an element).
o   Can circles of both the boxes A & B represent atoms of the same element?
o   Define an element in your own words.

Development

Activity 1

·         Divide students in groups; provide different colored paper clips to each group and say:
·         A green paper chip represents a hydrogen atom (symbol H).
·         A red paper clip represents an oxygen atom (symbol O).
·         A blue paper clip represents a carbon atom 9symbol C).
·         Ask students to hold one red paper clip in each hand and again ask. Can you consider it an atom?
·         instruct students to:
o   Combine two red paper clips and show it to the teacher. (Ask: what is it? is this an atom or something else?)
o   Introduce the term “molecule”. Tell students that atoms combine to form a molecule. When two oxygen atoms combine they form an oxygen molecule.
o   Ask: can different atoms form a molecule? (Yes/No)
o   Yes, write the formula of H2O (water) on board and ask groups to name atoms present in H2O.
o   Students to attach two green paper clips with one red paper clip. This is the model of H2O.
o   Ask students to form the structure / model of CO2 (Carbon dioxide) by using paper clips of respective colors. (2 red paper clips with one yellow paper clip). Give feedback if required.

Activity 2

·         Introduce “mixture” and write its definition on board. “When two or more than two substances are mixed in such a way that no new substance is formed”.
Step 1:
Divide students in groups and instruct them to:
o   Take some sulfur crystals in a china dish.
o   Mix them with some iron filings.
o   Observe the mixture whether its constituents have lost their original properties or not.
o   Move a bar magnet in the mixture.
o   Observe what happens.
o   Show the result to the teacher.
·         Ask how is it a mixture? (Explain it is a mixture because iron and sulfur can be
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·        Step 2:
Divide students in groups. Give them material and instruct them to:
o   Mix iron filings with sulfur crystals in a china dish.
o   Heat the mixture strongly.
o   Observe what happens with iron and sulfur.
o   Let the matter cool to room temperature.
o   Move a bar magnet in the substance present in china dish.
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Conclude the activity by asking:

·         Q1:Why don’t iron filings separate from the substance formed on heating the mixture?
(Expected response: Due to heating, the iron filings reacted with sulfur chemically and formed a new compound)
·         Q2: What type of substance is formed on heating the mixture of sulfur and iron?
(Expected response: Iron sulphide)
·         Q3: give examples of some common compounds and mixtures.
(Expected response: Compounds: water, common salt, Mixture: Air, steel, ice cream)

Sum up / Conclusion

Explain children that we learn:
·         The smallest particle of an element is atom.
·         Atoms of different elements have different sizes and combine to form compounds.
·         Atoms can’t exist independently except that of noble gases.
·         Components of mixtures can be separated by physical methods.
·         Molecules of element have same kind of atoms while molecules of compound have different kind of atoms.

Assessment

Ask:
·         What is an atom?
·         What is the difference between an atom and a molecule?
·         What is H, C, O?
·         Tell them that atoms/elements are recognized by “symbols” which is the shortest name of an element. Show students a periodic table and have a brief discussion on the symbols of the following like He, Na, N, Ca, fe elements.

Follow up

·         Make the following models with the help of the colored paper clips.
·         
·         List down 4-4 examples of mixtures & compounds occurring/present in our surroundings.

 

 

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