Nuclear Atom

Chem. Activity 1: The Nuclear Atom

Model: Schematic Diagrams for Various Atoms

1H and 2H are isotopes of hydrogen.     ¹²C and ¹³C are isotopes of carbon.

 

• Adapted from Moog, R. and Farrell, J., Chemistry: A Guided Inquiry. 5th ed. John Wiley & Sons: New York, 2012.

Critical Thinking Questions

1. How many protons are found in ¹²C? ¹³C? ¹³C ^–?

-Exploration since a careful systematic search or inquiry is required for the question to be answered satisfactorily

-Directed because the question is controlled and should be answered within the given parameters

2. How many neutrons are found in ¹²C? ¹³C? ¹³C ^–?

-Exploration question it requires systematic consideration to determine he number of neutrons

-Directed because the requirements of the question are controlled

3. How many electrons are found in ¹²C? ¹³C? ¹³C ^–?

-Application question because it involves implementing a concept to test for comprehension of concepts

Directed because the nature of the question has been regulated to yield specific answer

4. Based on your answers to CTQs 1-3, what do all carbon atoms (and ions) have in common?

-Application question since it is demonstrating relevance or practical use of the concepts already learned

Directed because it is guided, oriented or assigned to the learner so that it can generate specific responses.

5. Based on the model, what do all hydrogen atoms (and ions) have in common?

-Application question because it is scrutinizing memorizing ability of students

-Directed because it is subject to guidance

6. What is the significance of the atomic number, Z, above each atomic symbol in the periodic table?

-Application question owing to the fact that it is bringing out the relevance or significance of lessons learned

-Concept invention because the idea has to be conceived in the mind when discussing the significance of atomic number.

7. Based on your answer to CTQ 6, what do all nickel (Ni) atoms have in common?

-Application question because the concept is being exercised to demonstrate relevance

-Concept invention since creative thinking is required

8. In terms of the numbers of protons, neutrons and electrons:
9. Why does the notation ¹³C^– have a negative sign in the upper right hand corner?

-Application because implementing knowledge attained is involved in the question

-Exploration because a careful though is demanded

What feature distinguishes a neutral atom from an ion?

-The fact that it entails executing knowledge it is an application question

-Exploration question because probing the available parameters requires adequate examination

1. Provide an expression for calculating the charge on an ion.

-Since it entails execution of the knowledge acquired, it is an application question

9. Determine the number of protons, neutrons, and electrons in one ¹H⁺ ion. Explain how you found your answer.

-Exploration question owing to the fact that it is inquiring several variables. It is equally an application question since the process entails describing a concept

10. What structural feature is different in isotopes of a particular element?

-Application question because a concept learned is being implemented

Divergent question since the responses to be given for the question might differ

11. How is the mass number, A, (left-hand superscript next to the atomic symbol as shown in the Model) determined (from the structure of the atom)?

-It is an application question because the learner should apply critical thinking skills

-Concept invention is also necessary in the above question because the answer needs to be designed properly

12. Show that the mass number and charge given for ¹⁶O^2– and ²³Na⁺ are correct in Model 1.

-An application question because the right answers require thorough evaluation

-Exploration because investigation, study or research is required several variables ought to be considered in answering the question

13. Based on the information in Model 1, where is most of the mass of an atom, within the nucleus or outside of the nucleus? Explain your reasoning using grammatically correct English sentences.

-An application question since it demands adequate discussion and/or critical analysis

-Directed because the orientation of the anticipated answer has been dictated

Exercises

1. Complete the following table.

Questions 1-5 are all directed. The answers to be given in all the five questions are definite because the individual questions have been regulated.

Isotope	Atomic Number Z	Mass Number A	Number of Electrons
31P	15
18O			8
	19	39	18
		58

 

2. What is the mass (in grams) of a) one ¹H atom? b) one ¹²C atom?

-Since it is probing a larger section of variables, it is an exploration question

– Directed since answers are supposed to be definite. The questions have been controlled

3. What is the mass (in grams) of 4.35 × 10⁶ atoms of ¹²C?

-Exploration question since multiple factors are being put into consideration to attain the required response

– Directed since answers are supposed to be definite. The questions have been controlled

4. What is the mass (in grams) of 6.022 × 10²³ atoms of ¹²C?

-Exploration because several aspects are under consideration

– Directed since answers are supposed to be definite. The questions have been controlled

5. What is the mass (in grams) of one molecule of methane which has one ¹²C atom and four ¹H atoms, ¹²C¹H₄?

-An exploration question because it is inquiring a large data set in order to obtain an appropriate answer

– Directed since answers are supposed to be definite. The questions have been controlled

6. a) Define mass number. b) Define atomic number.

-Inspection, probe and examination are required hence it is an exploration question

-it is a directed question because a specific response is expected

7. Indicate whether the following statement is true or false and explain your reasoning. An ¹⁸O atom contains the same number of protons, neutrons, and electrons.

-Application question because logical thinking is vital for a proper feedback

-Divergent because varying answers can be given from the same question

8. How many electrons, protons, and neutrons are found in each of the following?

24_Mg    23_Na+  35_Cl     35_Cl–   56_Fe3+            15_N      16_O2– 27_Al3+

-Exploration question because it is scrutinizing multiple aspects

-It is also directed because the whole question is regulated to give a particular feedback

9. Complete the following table.

Isotope	Atomic Number Z	Mass Number A	Number of Electrons
	27	59	25
14N
	3	7	3
	3	6	3
58Zn2+
19F–

 

-Exploration question because it is examining several variables.

The question is also directed because specific answers are expected

10. Using grammatically correct English sentences, describe what the isotopes of an element have in common and how they are different.

-Application question because logical reasoning is vital

-Directed since it is subject to control or guidance

Problems

1. Estimate the mass of one ¹⁴C atom (in amu) as precisely as you can (from the data in the model). Explain your reasoning.

-Application question because execution of knowledge that was acquired sometimes back is taking place

-Divergent question since answers given can differ

2. Use the data in Model 1 to estimate the values (in amu) of a) the mass of an electron, b) the mass of a proton, and c) the mass of a neutron.

-Application because a learner should think deeply and logically when answering the question

-Divergent because the answers can differ from one response to another

3. Te mass values calculated in Problem 2 are only approximate because when atoms (up through iron) are made (mainly in stars) from protons, neutrons, and electrons, energy is released. Einstein’s equation E = mc² enables us to relate the energy released to the mass loss in the formation of atoms. Use the known values for the mass of a proton, 1.0073 amu, the mass of a neutron, 1.0087, and the mass of an electron, 5.486 × 10^-4 amu, to show that the mass of a ¹²C atom is less than the sum of the masses of the constituent particles.

– Since knowledge is being exercised, it is an application question

-It is also directed be because specific values have been issued to be used in the calculation

HOW MUCH IS TOO MUCH?

1. Pre-Activity Questions:
2. What are the chemical formulas for water, hydrogen, and oxygen molecules?

-Application because knowledge attained is fundamental in answering it

-Directed question because it has definite  values when answered

1. Write the balanced chemical equation for the reaction of hydrogen molecules with oxygen molecules to form water molecules.

-Application question because the understanding of learners is being tested

-Concept invention because the idea is being recreated

Model 1: Hydrogen and oxygen gas molecules react to form water vapor molecules
2. Critical Thinking Questions
1. Circle all the water molecules depicted in cartoon “B”.

-Application because concept understanding is being tested

-Concept invention since the idea is being regenerated

2. In reactions A, B, and C, are hydrogen atoms shown as solid or open circles? Are oxygen atoms shown as solid or open circles? Use your answer to make a legend for the model.

-Exploration and application questions because knowledge operation and examination of a large set is taking place

3. What is the ratio of hydrogen to oxygen molecules that react in: a. reaction A?

-Application question because the understanding of learners is being probed

Compare your group’s answer to the answer of another group, and explain any differences.

-Exploration because it can be expounded or discussed in a broad manner

Concept invention since comparing group’s work.

4. What is the ratio of hydrogen molecules that react to water molecules that form in:
5. reaction A?
6. reaction B? 111
7. reaction C?

The quantity of oxygen molecules is doubled in reaction C compared to reaction B; does the quantity of water molecules produced increase?

-Concept invention because critical thinking is necessary

-Exploration question owing to the fact that inquiry, search and survey are required

Why do oxygen molecules appear on the right side of the arrow in reaction C?

-Exploration question because it entails investigating several possibilities

-Concept invention because conception, design and creativity is required

Which reactant limits the quantity of H₂O produced in reaction C? Which reactant is in excess?

-Application question since the ability to recall is prudent

-Directed since the parameters of the question are confined or regulated

Should 0₂ be included as a product in the balanced chemical equation for reaction C? Explain your answer using a complete sentence. All members of the group should have the sentence.

Determine the number of water molecules produced in a reaction mixture containing

1. 10 hydrogen molecules and 10 oxygen molecules.
2. 30 hydrogen molecules and 13 oxygen molecules.
3. 3 dozen hydrogen molecules and 2 dozen oxygen molecules.

-Application because the comprehension of learners is being investigated

-Concept invention due to creativity required to answer the question

Model 2: Moles of hydrogen and oxygen gas molecules react to form moles of water vapor molecules.

10. How many moles of hydrogen react and how many are left over in reaction II

-Application question because the understanding of learners is being tested

11. What is the ratio of moles of hydrogen to moles of oxygen that react in:
12. reaction I?
13. reaction II? Q
14. reaction III?

-Application since comprehension ability is the main test

Directed question because no external values can be used in the computations

12. Should H₂ be included as a product in the balanced chemical equation for reaction III? Justify your reasoning using a complete sentence; compare your group’s sentence to that of another group. No

-Exploration because  more than one possibility is being examined. I is also divergent due to different reasoning

13. Determine the number of moles of water produced a reaction mixture containing

-Application question since knowledge is being verified for validity and it also directed because of specific values to be used in the calculation

1. 6 moles of oxygen and 13 moles of hydrogen.
2. 32.0 g of oxygen and 1.01 g of hydrogen.
3. For each reaction mixture in #13, identify the limiting reagent

-An exploration question since several possibilities are present and an  application question because knowledge is being applied.

15. Consider the balanced chemical equation, 2N0(0+ 02(0-4 2NO2 (g)
16. If 30.0 grams of NO react, what is the mass of 02 required, and what is mass of NO2 produced?
17. If 30.0 grams of 02 react, what is the mass of NO required, and what is mass of NO2 produced?
18. A mixture of 30.0 grams each of 02 and NO reacts to form NO2. Which is the limiting reagent, 02 or NO? Explain your answer using grammatically correct English sentences.

-Both an exploration and an application question because several values are being examined while the knowledge attained is also put to practice.

86. A student calculates that 86.3 grams of NO2 are produced from a reaction mixture of 30.0 grams each of 02 and NO. Is this student correct? Explain your answer using grammatically correct English sentences.

-Exploration question since the student has to investigate various possibilities of tackling the question and present the answer in the most correct manner

16. Solid Zn and 12 (iodine) react to form solid zinc iodide, Znl2. 12 has a higher molar mass than Zn.
17. Write the balanced chemical equation for this reaction.

Application question because the knowledge acquired is being put to test

50. If 50.0 grams each of Zn and 12 react, which element will be completely consumed in this reaction? Application question because the knowledge acquired is being tested

Answer this without using a calculator.

1. Which element is the limiting reagent?
2. Calculate the mass of Zn12 that forms.
3. Calculate the mass of the excess element that remains unreacted.

-Application because the knowledge is being put into action.

17. Acetylene gas, HCCH (or C2H2) reacts with hydrogen gas, H2, to form ethane gas, C2H5.
18. Write the balanced chemical equation for this reaction.
19. What mass of ethane can be produced from 40.4 grams of hydrogen?
20. Calculate the mass of ethane produced from a mixture of 15.0 grams each of HCCH and H2.

-Application question since a concept is being executed

-Directed since the values given are to be used in the computations

18. Titanium metal, Ti, is produced from the reaction of TiC14 with Mg metal; MgCl2 is the other product. Write the balanced chemical equation for this reaction, and calculate the mass of Ti produced from the reaction given 6.8×104 grams of TiCl4 and 4.2×104 grams of Mg.

-Application question since the past learned concepts are being tested

-Directed question because only the values given are to be used in the calculation

Learning cycle
The learning cycle exists in the above questions because the whole module has been tested procedurally with the aim of assisting learners recall concepts from the simplest to more complicated ones.

Learning objectives for the assignment

1. Discuss and distinguish chemical reactions
2. Elaborate your current topical learning cycle and the various phases

• Demonstrate understanding of and approaches for answering questions successfully