Theme | Decoding an atom and its structure |
Relevant Grades | Class 8, 9 & 10 |
Key Learning Objectives |
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Session Duration | 1 Hour (Approximately) |
- THE MISSION
The atoms of all matter existent on earth have lost their form and structure and are moving around with no uniformity and moving in all directions. The atoms are starting to break down and hence all the matter that is made of atoms is starting to break down and earth is becoming dust with no form or structure. Imagine you are an atom and you will have to build all the atoms and its components back to shape with correct structure, charge of the various particles so that matter comes to form and the various objects on Earth come back to shape. In this level of the game, there are other unknown particles that are sent from outer space by aliens that are looking to destroy the atoms and prevent matter from having form and structure on Earth. The gamer who strategically plays an atom has to prevent all the foreign particles from destroying the atoms on earth and also structure the atoms to form matter within a span of 30 minutes. On completion of both these tasks, the atom earns 100 points of extra charge to fight against the enemies as well as a power such that you will never be broken as an atom. In the next level of the game, you are an atomic researcher and are charged with the responsibility of separating isotopes from isobars on the norms that are present for them to be separated and should be completed within 10 minutes and the researcher earns a lifetime award and will be awarded 200 points for their remarkable contribution.
- CONCEPTS
Atoms are the basic building blocks of matter. Different kinds of matter exist because there are different kinds of atoms present in them.
- Charged particles in matter
When Whenever we rub two objects together, they become electrically charged. This is because atoms contain charged particles in them. Therefore, atoms can be divided further into particles i.e. proton, electron and neutron.
- Protons were discovered by Ernest Rutherford, in his famous gold foil experiment.
- Electrons were discovered by J.J. Thomson, in his cathode ray tube experiment.
- Neutrons were discovered by James Chadwick.
Atoms consist of protons and electrons in a balanced proportion. Protons exist in the interiors of the atom and electrons exist in the exteriors of the atom. Therefore, electrons can be removed from an atom.
Failure of Dalton’s Atomic Theory:
The postulates of the atomic theory by John Dalton:
- The matter is made up of tiny particles called Atoms that cannot be divided.
- Atoms are never formed or destroyed during a chemical reaction.
- Atoms of an element exhibit the same nature. They have the same size, mass, and character.
- Atoms of different elements exhibit variant nature. They do not have the same characteristics.
- Atoms form compounds by combining in a ratio of whole numbers.
- A compound contains a constant number and kinds of atoms
Dalton suggested that atoms can neither be created nor destroyed and are indivisible. But the discovery of electrons and protons in atoms lead to failure of this aspect of Dalton’s theory.
Thomson’s Model of an Atom:
According to J.J. Thomson, the structure of an atom can be compared to Christmas pudding where electrons are present inside a positive sphere.
An atom is composed of a positively charged sphere in which electrons are embedded. Atom is neutral as the positive and negative charges are equal in proportion.
Rutherford’s Model of an Atom:
- He experimented with thin gold foil by passing alpha rays through it.
- He expected that the gold atoms would deflect the Alpha particles.
Observations | Inferences |
Alpha particles which had high speed moved straight through the gold foil | Atom contains a lot of empty space |
Some particles got diverted a by slide angles | Positive charges in the atom are not occupying much of its space |
Only one out of 12000 particles bounced back | The positive charges are concentrated over a particular area of the atom. |
Thus, Rutherford gave the nuclear model of an atom based on his experiment which suggests that:
- Atoms contain a lot of unoccupied space
- There is a heavily positively charged substance present in the centre of the atom which is called the nucleus
- The nucleus contains an equal amount of positive and negative charge
- Nucleus of an Atom
- The nucleus is located at the centre of the atom
- All the mass of the atom is because of the nucleus.
- The electrons revolve around the nucleus in circular parts which are called Orbits
- If we compare the size of the atom and nucleus, the nucleus is much smaller than the atom
Drawbacks of the Nuclear Model of an Atom
The Nuclear Model of the Atom failed to explain how an atom remains stable despite having positive and negative charges present in it. Maxwell has suggested a theory according to which if any charged particle moves in a circular motion it radiates energy. So, if electrons start moving in a circular motion around the nucleus they would also radiate some energy which would decrease at the speed of the electrons. As a result, they would fall into the nucleus because of its high positive charge.
What are nucleons? – Protons and Neutrons are collectively called Nucleons.
Bohr’s Model of an Atom
Bohr suggested that:
- Electrons spin around the nucleus in an individualized separate path or unattached orbit.
- The electrons do not emit any energy while moving Indies special orbits.
- These orbits are also called Energy Levels.
- They are represented using letters or numbers as shown in the figure below:
- The Neutrons
- Chadwick discovered that there is another subatomic particle present in the atom. This particle carries no charge and is known as a Neutron. Therefore, we can conclude that atom consists of three types of particles:
Electrons | which carry a negative charge |
Protons | which carry a positive charge |
Neutrons | they are neutral |
The distribution of electrons in different shells or orbits:
- If Orbit number = n
- Then number of electrons present in an Orbit = 2n2
- So, for n =1
- Maximum electrons present in shell – K = 2 * (1)2 = 2
- The outermost shell can contain at most 8 electrons.
- The shells in an atom are filled in sequence.
- Thus, until the inner shells of an atom are filled completely the outer shells cannot contain any electrons.
- Valency
- Valence Electrons – Electrons existing in the outermost orbit of an atom are called Valence Electrons.
- The atoms which have completely filled the outermost shell are not very active chemically.
- The valency of an atom or the combining capacity of an atom is given by the number of elements present in the outermost shell. For Example, Helium contains two electrons in its outermost shell which means its valency is two. In other words, it can share two electrons to form a chemical bond with another element.
Valency in such cases is generated by subtracting the number of electrons present in the outermost orbit from octet (8). For example, oxygen contains 6 electrons in its outermost shell. Its valency is calculated as: 8 – 6 = 2. This means oxygen needs two electrons to form a bond with another element.
Atomic Number of an Element
Atomic Number (Z) = Number of protons in an atom
Mass Number of an Element
Mass Number = Number of protons + Number of neutrons
- Isotopes
- The atoms of an element can exist in several forms having similar atomic numbers but varying mass numbers.
- Isotopes are pure substances.
- Isotopes have a similar chemical nature.
- Isotopes have distinct physical characteristics.
Where can we use Isotopes?
- The fuel of Nuclear Reactor – Isotope of Uranium
- Treatment of Cancer – Isotope of Cobalt
- Treatment of Goiter – Isotope of Iodine
Example: Consider two atomic species namely U and V. Are they isotopes?
| U | V |
Protons | 5 | 5 |
Neutrons | 5 | 6 |
Mass Number | 5 + 5 = 10 | 5 + 6 = 11 |
Atomic Number | 5 | 5 |
From the above example, we can infer that U and V are isotopes because their atomic number is the same.
Isobars
The atoms of several elements can have a similar mass number but distinct atomic masses. Such elements are called Isobars.
GAME DESIGN
- Problem statement
The atoms of all matter existent on earth have lost their form and structure and are moving around with no uniformity and moving in all directions. The atoms are starting to break down and hence all the matter that is made of atoms is starting to break down and earth is becoming dust with no form or structure. Imagine you are an atom and you will have to build all the atoms and its components back to shape with correct structure, charge of the various particles so that matter comes to form and the various objects on Earth come back to shape. In this level of the game, there are other unknown particles that are sent from outer space by aliens that are looking to destroy the atoms and prevent matter from having form and structure on Earth. The gamer who strategically plays an atom has to prevent all the foreign particles from destroying the atoms on earth and also structure the atoms to form matter within a span of 30 minutes. On completion of both these tasks, the atom earns 100 points of extra charge to fight against the enemies as well as a power such that you will never be broken as an atom. In the next level of the game, you are a atomic researcher and are charged with the responsibility of separating isotopes from isobars on the norms that are present for them to be separated and should be completed within 10 minutes and the researcher earns a lifetime award and will be awarded 200 points for their remarkable contribution.
- Game design overview
The atoms of all matter existent on earth have lost their form and structure and are moving around with no uniformity and moving in all directions. The atoms are starting to break down and hence all the matter that is made of atoms is starting to break down and earth is becoming dust with no form or structure. Imagine you are an atom and you will have to build all the atoms and its components back to shape with correct structure, charge of the various particles so that matter comes to form and the various objects on Earth come back to shape. In this level of the game, there are other unknown particles that are sent from outer space by aliens that are looking to destroy the atoms and prevent matter from having form and structure on Earth. The gamer who strategically plays an atom has to prevent all the foreign particles from destroying the atoms on earth and also structure the atoms to form matter within a span of 30 minutes. On completion of both these tasks, the atom earns 100 points of extra charge to fight against the enemies as well as a power such that you will never be broken as an atom. In the next level of the game, you are a atomic researcher and are charged with the responsibility of separating isotopes from isobars on the norms that are present for them to be separated and should be completed within 10 minutes and the researcher earns a lifetime award and will be awarded 200 points for their remarkable contribution. The gamer has to strategically plan equipment and tools to fight the enemies and win the game and restore earth and will be rewarded at each step of the game adequately.
- How to design the game?
- Step I
The atoms of all matter existent on earth have lost their form and structure and are moving around with no uniformity and moving in all directions. The atoms are starting to break down and hence all the matter that is made of atoms is starting to break down and earth is becoming dust with no form or structure. Imagine you are an atom and you will have to build all the atoms and its components back to shape with correct structure, charge of the various particles so that matter comes to form and the various objects on Earth come back to shape. In this level of the game, there are other unknown particles that are sent from outer space by aliens that are looking to destroy the atoms and prevent matter from having form and structure on Earth. The gamer who strategically plays an atom has to prevent all the foreign particles from destroying the atoms on earth and also structure the atoms to form matter within a span of 30 minutes.
Hint: The enemy particles will increase by 50% every 10 minutes and they get charged every time the atom fails to destroy the enemy particles by the atoms and the charge of the atoms fighting against the particles reduces by 10% every time it fights an enemy particle. If the game is not completed within 30 minutes, the matter can never be structured back to normal and all the atoms disintegrate. The atom earns extra charge to sustain for another 100 years and 100 points.
- Step II
In the next level of the game, you are an atomic researcher and are charged with the responsibility of separating isotopes from isobars on the norms that are present for them to be separated and should be completed within 10 minutes and the researcher earns a lifetime award and will be awarded 200 points for their remarkable contribution. The gamer has to strategically plan equipment and tools to fight the enemies and win the game and restore earth and will be rewarded at each step of the game adequately.
Hint: The level should be completed within 10 minutes or else the isotopes and isobars will form an inseparable mixture and you will lose the 200 points as well as the lifetime that would have been awarded to you.
- Step III
The atoms will form molecules and elements after these two steps which will again be destroyed by enemy particles.
Hint: The completion of this step successfully leads to closure of the game and the player finally earns 100 points for this step.
- ASSESSMENT
Learning Objective Based Evaluation (0-1) | Q1 | Q2 | Q3 | Q4 | ||
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Higher Order Thinking Skills | Problem Solving | Critical Thinking | Innovation | Creativity | ||
Q5 | Q6 | Q7 | Q8 | Q9 | Q10 | |
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Learning Objective Based Evaluation Total Score | /4 |
Higher Order Thinking Skills Total Score | /8 |
Total Score | /12 |
Learning Objective Based Evaluation
1 point Questions:
Q1. Which of the following are neutrally charged particles?
- Neutrons
- Electrons
- Protons
- None of the above
Q2. Which of the following statements of Isotopes is false?
- The atoms of an element can exist in several forms having similar atomic numbers but varying mass numbers.
- Isotopes are impure substances.
- Isotopes have a similar chemical nature.
- Isotopes have distinct physical characteristics.
Q3. Which of the following is true about isobars?
- Similar mass number but different atomic masses
- Different mass number but similar atomic masses
- None of the above
Q4. What is the mass number of an element?
- Number of protons + Number of Neutrons
- Total Number of electrons
- Total Number of protons
- None of the above
Evaluation of HOTS (Higher Order Thinking Skills)
Identification of the Problem Statement:
Q5. What is the goal of the game that you have designed? (1 point)
_______________________________________________________________
Q6. Does the game designed solve the problem? Justify your answer. (1 point)
_______________________________________________________________
Solution of the Problem Statement:
Q7. What is your understanding of the atomic structure? (1 point)
_______________________________________________________________
Q8. What are the ways in which the various atomic models can be understood and implemented in science? (1 point)
_______________________________________________________________
Innovation in the Problem Statement:
Q9. What are the innovative aspects of the solution for which the game is designed? (2 points)
_______________________________________________________________
Creativity in the Game Design:
Q10. Describe and explain the unique design elements used in the game. (2 points)
_______________________________________________________________
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