Atomic Structure and Isotopes

Lesson Plan of Atomic Structure and Isotopes

General Science Grade VII

Students’ Learning Outcomes

·         Describe the structure of an atom.
·         Define the term isotopes.
·         Explain uses of isotopes in medicines and agriculture.

Information for Teacher

·         Atoms are the smallest particle of an element.
·         An atom is the simple form of an element that can take part in a chemical reaction.
·         Atoms are basic building blocks of matter.
·         The word atom is derived from the Greek word atom which means indivisible.
·         Atoms are composed of three types of particles: protons, neutrons, and electrons.
·         Protons have a positive (+) charge, neutrons are neutral while electrons have a negative charge (-)
·         Atoms of a given element which have the same number of protons but different numbers of neutrons are called isotopes. Thus, isotopes of an element have same chemical properties but different physical properties.
·         Isotopes are often used in medical research and therapy for a variety of diseases and genetic disorders.
·         Isotopes are mostly used in various uses in medicine, to diagnose and treat illnesses.
·         They are also used widely in biochemical research in various fields like chemistry, physics, neurosciences and biology.

Concept Map

Material / Resources

A ball made of plasticize, different colored marbles or stone (chocolate bun ties can also be used) glue, small rosary beads,

Worm up activity

·         Teacher can start the lesson by asking what is everything made of? Every building, every person, every object? (Students will answer matter and atoms). They can be taught about atomic structure by using following activity:


·         Teacher can now explain structure of atom by showing children the model of hydrogen atom made from ball and marbles.
·         In the model the ball may be depicted as the nucleus of the atoms.
·         The marbles of orange color will represent protons. Put these in the nucleus. There are no neutrons in a hydrogen atom.
·         Use a bendable wire to make the orbital and add rosary beads. Ask children to keep on rotating the beads to show movement of electrons. Leave 2 inches distance between nucleus and electrons.
·         Teacher should explain about the different types of charges on electrons and protons.
·         Teacher should explain children that electrons are always moving. They spin very quickly and in any direction around the nucleus.
·         Draw following pictures on board to give the spin and orbital concept.


Activity 1

·         Teacher can divide the class in three groups and ask children to make models of carbon and helium atom.
·         Teacher will write the following data on board.
·         Carbon: 6 protons, 6 neutrons and 6 electrons.
·         Helium: 2 protons, 2 neutrons and 2 electrons.
·         Instructions should be given to children that electrons are present around the nucleus in shells. Shells or orbitals serve as home of electrons.
·         First shell can have two electrons. 2nd shell can have 8 electrons and third can have up to 18 electrons.
·         Move around the class and assist children in making models. Also ask them questions like where will be the protons, what will be their charge.
·         Ask both groups to come for a presentation and explain their atomic models.
·         The models should look have the arrangement given below.

Activity 2

·         Teacher can draw the following diagram on board.
·         Img
·         Ask the children to identify the four parts of the atom that are pointed out by arrows in the diagram above.
·         Describe the electrical charges of the structures that are labeled 1, 2, and 3 in the diagram.
(Expected response: Number 1 is the electrons, 2 is the proton, 3 is the neutron, and 4 is the nucleus). Charges: the electron is negative, proton is positive and neutron is neutral.

Activity 3

·         Teacher can explain students what are isotopes and where are they used. To strengthen their concepts more, she can tell that 
·         Colbat-60 is used in food preservation. It is also used to sterilize medical equipment (e.g. gloves, syringes, cotton balls, etc.) as it produces gamma radiations.
·         Medical isotopes are also used in treatment and diagnosis of diseases.
·         Show students the following picture and ask to explain the process.
·         After listening to their explanations tell them that using radiations produced by isotopes is a method of treating food in order to make it safer to eat.
·         Tell them that this method is also used to export fruits and vegetables to other countries as food life is increased.
·         Students can be asked to prepare a list of other processes where isotopes can be used.

Sum up / Conclusion

·         Teacher may conclude the lesson by telling children that they have learnt.
·         An atom has subatomic particles called protons, neutrons, electrons.
·         Protons have positive charge, electrons have negative while neutrons have no charge.
·         Isotopes are of great medical and industrial use.


·         Teacher may ask some questions at the end of the lesson to ensure that they now know:
o   What is the position of electrons, protons and neutron in the structure of any atom?
o   What are types of charge on electrons and protons and neutrons?
o   Define the term isotopes.
o   What are uses of isotopes in food and medicine industry?

Follow up

·         Show students the following picture of destruction in japan caused by an isotope of hydrogen. 
Tell them the interesting fact that all new clocks and watches made in japan have the same time 10:10 as bomb was dropped at this time. It is in the memory of those who died in Hiroshima Nagasaki nuclear attack. Ask them to find out which isotope of hydrogen was used for it?

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