NITROGEN : GENERAL PROPERTIES OF NITROGEN FAMILY .

Subject :Chemistry

Term : Second Term

Week :Week 6

Topic : NITROGEN : GENERAL PROPERTIES OF NITROGEN FAMILY .

Objective: By the end of the lesson, students will be able to:

1. Identify the physical and chemical properties of nitrogen.
2. Explain the uses of nitrogen in various industries.
3. Describe the nitrogen cycle and its importance in the ecosystem.

Materials:

• Whiteboard and markers
• Printed copies of review questions and activities
• Audiovisual aids (optional)

WEEK SIX

DATE: _________

TOPIC:NITROGEN

CONTENT

• General Properties of Nitrogen Family.
• Laboratory Preparation and Industrial Preparation of Nitrogen.
• Properties and Uses of Nitrogen. 
• Nitrogen Cycle.

Nitrogen is a chemical element with the symbol N and atomic number 7. It is the most abundant element in Earth’s atmosphere, making up around 78% of the air we breathe.

Here are some examples to help you understand more about nitrogen:

1. Nitrogen gas: As mentioned, nitrogen gas makes up a large part of the Earth’s atmosphere. This gas is colorless, odorless, and mostly inert, meaning it does not react with other chemicals under normal conditions.
2. Fertilizers: Nitrogen is an essential nutrient for plant growth. Farmers use nitrogen-rich fertilizers to help their crops grow faster and bigger. Ammonia, urea, and ammonium nitrate are common nitrogen-based fertilizers.
3. Protein: Nitrogen is a key component of protein, which is essential for building and repairing tissues in the body. Foods rich in protein include meat, fish, beans, and nuts.
4. Explosives: Nitrogen is also used to make explosives. For example, ammonium nitrate can be used in mining and construction to blast through rocks.
5. Airbags: Nitrogen gas is also used to inflate airbags in cars. Unlike oxygen, which can cause a fire if it comes into contact with a spark or flame, nitrogen is non-reactive and therefore safer to use in this application

GENERAL PROPERTIES OF NITROGEN FAMILY (GROUP VA ELEMENTS)

The nitrogen family, also known as Group VA or Group 15, includes five elements: nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). Here are some of the general properties of the nitrogen family:

1. Electronic Configuration: The elements in Group VA have five valence electrons in their outermost shell.
2. Non-metals to Metalloids: Nitrogen and phosphorus are non-metals, while arsenic and antimony are metalloids, and bismuth is a metal.
3. Increasing Atomic Size: As you move down the group, the atomic size increases. This is due to the increase in the number of occupied energy levels.
4. Similar Chemical Properties: The elements in Group VA have similar chemical properties because they all have the same number of valence electrons. They tend to form compounds with other elements by sharing electrons, which results in covalent bonds.
5. Electronegativity: The electronegativity of the elements in this group decreases as you move down the group. This means that bismuth has the lowest electronegativity while nitrogen has the highest.
6. Oxidation States: The elements in Group VA can have various oxidation states. For example, nitrogen can have oxidation states ranging from -3 to +5, while phosphorus can have oxidation states ranging from -3 to +5.
7. Ability to form Pnictogen bonds: The Group VA elements are known to form unique chemical bonds called pnictogen bonds, which are a type of weak interaction that involves the lone pair electrons of these elements

The group V elements include: Nitrogen, Phosphorus, Arsenic, Antimony and Bismuth. There are more differences than similarities between the elements in this group.

1. Nitrogen is a diatomic gas and does not exhibit allotropy. Phosphorus is a typical non-metal and exhibits allotropy. Arsenic and Antimony are metalloid; while bismuth is a metal.
2. Nitrogen is a colourless gas. Phosphorus exists in variety of allotropic forms like white and red phosphorus. Arsenic exists as a dull grey metallic solid. Antimony and bismuth is silvery-white solid.
3. Nitrogen is the most electronegative element in the group. It combines with metals and non-metals to form a variety of compounds.

Phosphorus is less electronegative than nitrogen and forms a wide range of compounds with metals, non-metals, and metalloids. Arsenic is more metallic than phosphorus and can form compounds with both metals and non-metals. Antimony is a stronger metallic element than arsenic and forms stable compounds with both metals and non-metals. Bismuth is the least reactive element in the group and forms compounds mostly with non-metals.

In terms of their physical properties, the group V elements also differ in their melting and boiling points, densities, and solubilities in various solvents

Evaluation

1. Which of the following elements is part of the nitrogen family? A. Carbon B. Nitrogen C. Oxygen D. Fluorine
2. What is the atomic number of nitrogen? A. 6 B. 7 C. 8 D. 9
3. Which of the following elements is a metalloid in the nitrogen family? A. Nitrogen B. Phosphorus C. Antimony D. Bismuth
4. What is the most abundant gas in the Earth’s atmosphere? A. Oxygen B. Nitrogen C. Carbon dioxide D. Hydrogen
5. Which of the following elements does not exhibit allotropy? A. Nitrogen B. Phosphorus C. Arsenic D. Antimony
6. Which of the following is a common nitrogen-based fertilizer? A. Carbonate B. Ammonia C. Sulfate D. Chloride
7. Which element in the nitrogen family is the most electronegative? A. Nitrogen B. Phosphorus C. Arsenic D. Bismuth
8. Which of the following elements can form pnictogen bonds? A. Nitrogen B. Phosphorus C. Arsenic D. All of the above
9. Which of the following elements is a diatomic gas? A. Nitrogen B. Phosphorus C. Arsenic D. Antimony
10. Which of the following is an example of a compound that contains nitrogen? A. H2O B. CO2 C. NH3 D. NaCl

ELECTRONIC CONFIGURATION

The electronic configuration of the group V elements is as follows:

Nitrogen = 7: 1s2 2s2 2p3

Phosphorus = 15: 1s2 2s2 2p6 3s2 3p3

Arsenic = 33: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p3

Antimony   = 51: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p3

NITROGEN 

Nitrogen occurs chiefly as a free element in the air. It makes up 78% by volume of the atmosphere. It also exists in combined form in many compounds e.g ammonia, urea, proteins etc. 

Nitrogen is a very important element in the Earth’s atmosphere, where it exists as a diatomic molecule (N2) comprising two nitrogen atoms held together by a strong triple covalent bond. This molecule makes up about 78% of the Earth’s atmosphere by volume.

In addition to its presence in the atmosphere, nitrogen also occurs in various compounds in nature. For example, nitrogen is a key component of amino acids, which are the building blocks of proteins. Nitrogen is also found in nucleic acids like DNA and RNA, as well as in many other biologically important molecules.

Nitrogen also occurs in compounds like ammonia (NH3) and urea (CO(NH2)2), which are important for plant growth and are used as fertilizers. These compounds are also used in the production of various industrial chemicals like nitric acid and explosives.

Overall, the abundance of nitrogen in the atmosphere and its presence in many important compounds make it an essential element for life on Earth

Electronic configuration is the arrangement of electrons in the energy levels or shells around an atom’s nucleus. The electronic configuration of nitrogen can be represented as 1s² 2s² 2p³.

Here’s a breakdown of what this means:

• The first number indicates the principal energy level or shell. In nitrogen, there are two electrons in the first shell and five electrons in the second shell.
• The letter represents the subshell. In nitrogen, there are two electrons in the s subshell and five electrons in the p subshell.
• The superscript number represents the number of electrons in that subshell. In nitrogen, there are two electrons in the 2s subshell and three electrons in the 2p subshell.

To understand this better, let’s take a closer look at the electron configuration of nitrogen.

Nitrogen has an atomic number of 7, which means it has seven electrons. These electrons occupy the first two shells or energy levels.

The first shell has a maximum of two electrons, which are in the 1s subshell. The second shell has a maximum of eight electrons and is divided into the 2s and 2p subshells. The 2s subshell can hold up to two electrons, while the 2p subshell can hold up to six electrons

In nitrogen, two electrons occupy the 2s subshell, and the remaining three electrons occupy the 2p subshell. The 2p subshell has three orbitals, each of which can hold a maximum of two electrons. In nitrogen, one electron occupies each of the 2p orbitals, and the remaining two electrons are paired in one of the orbitals.

Overall, understanding the electronic configuration of nitrogen helps us understand how it interacts with other elements to form compounds. For example, nitrogen forms covalent bonds with other elements by sharing its three unpaired electrons in the 2p subshell. This is seen in compounds like ammonia (NH3), where nitrogen shares its electrons with three hydrogen atoms

LABORATORY PREPARATION

From Air

It can be obtained from air by passing air through caustic soda to remove CO2 and 

overheated copper turnings to remove O2 respectively. The nitrogen obtained is not pure, it contains 1% by volume of rare gases and it is denser than air.

Pure nitrogen is obtained in the laboratory by chemical method. The following chemicals are used to prepare nitrogen.

1. Thermal decomposition of ammonium dioxonitrate (III)
2. NaNO2(aq)     +  NH4Cl(aq)     → NH4NO2(aq) +NaCl(aq)
3. NH4NO2(aq)     →   2H2O(l) + N2(g)

2. Thermal decomposition of ammonium heptaoxodichromate (VI)

(NH4)2Cr2O7(s)     →  Cr2O3(s)   +    4H2O(l)  +  N2(g)

3. Oxidation of ammonia by hot Copper (II) oxide

2NH3(g)     +   3CuO(s)      →    3Cu(s)      + 3H2O(g)  +  N2(g)

1. Reduction of dinitrogen (I) oxide by red-hot copper. 

N2O(g)       + Cu(s)        →    CuO(s)         +      N2(g)

INDUSTRIAL PREPARATION

Industrially, nitrogen is obtained by fractional distillation of liquid air.

EVALUATION

1. Write the electronic configuration of nitrogen and phosphorus.
2. Using balanced equations, state TWO methods of preparing nitrogen in the laboratory.

PHYSICAL PROPERTIES OF NITROGEN 

1. It is colourless, odourless and tasteless 
2. Pure nitrogen is lighter than air.
3. Slightly soluble in water
4. Melting point – 2100C  and   boiling point is -1960C
5. Nitrogen is a colorless, odorless, and tasteless gas at room temperature and standard pressure.
6. Pure nitrogen is slightly lighter than air, which means that it will tend to rise and collect near the top of a room or container.
7. Nitrogen is slightly soluble in water, meaning that a small amount of it can dissolve in water to form a weakly acidic solution.
8. Nitrogen has a relatively low melting point of -210 degrees Celsius and a very low boiling point of -196 degrees Celsius. These low temperatures make it possible to liquefy nitrogen under certain conditions, which is useful in a variety of industrial applications

CHEMICAL PROPERTIES OF NITROGEN 

1. It reacts with very electropositive metals to form nitrides3Mg(s)     +       N2(g)    →    Mg3N2(s)

2. It reacts with non – metals like hydrogen and oxygen to form ammonia and oxides respectively.N2(g)     +       3H2(g)      →   3NH3(g)N2(g)     +       2O2(g)      →   2N2O(g)
3. Nitrogen is a relatively inert gas and does not readily react with most other elements or compounds. However, it can react with very electropositive metals like magnesium to form nitrides, as shown in the example you provided.
4. Nitrogen can also react with non-metals like hydrogen and oxygen to form various compounds. For example, nitrogen can react with hydrogen gas to form ammonia (NH3), which is an important industrial chemical used in the production of fertilizers and other compounds. Nitrogen can also react with oxygen to form various nitrogen oxides, such as N2O (nitrous oxide) and NOx (nitrogen oxides), which are important pollutants in the atmosphere.
5. Nitrogen can also undergo various other chemical reactions, such as with halogens to form nitrogen halides, or with sulfur to form sulfur nitrides. These reactions are important in various chemical and industrial applications

USES 

1. It is used industrially to manufacture ammonia.
2. Liquid nitrogen is used as a cooling agent.
3. It is used as preservative in packaged foods to prevent rancidity.
4. Nitrogen is used industrially in the Haber-Bosch process to produce ammonia (NH3), which is a key component in fertilizers and many other industrial chemicals.
5. Liquid nitrogen is used as a cooling agent in a variety of applications, such as in cryogenic freezing of food, medical samples, and biological tissues. It is also used in the production of superconductors and as a coolant in computer systems.
6. Nitrogen gas is used in the food industry as a packaging gas to help prevent the oxidation of packaged foods, which can cause spoilage and rancidity. Nitrogen gas is an inert gas, which means it does not react with food or alter its flavor or texture.
7. Nitrogen is also used in the medical field for various purposes, such as in the production of pharmaceuticals, as a coolant in cryotherapy, and in the treatment of respiratory disorders.
8. In addition, nitrogen is used in various other industries, such as in the production of steel, as a shielding gas in welding, and as a pneumatic power source in air-powered tools and machinery

EVALUATION  

1. State TWO physical properties and TWO chemical properties of nitrogen.
2. Mention THREE uses of nitrogen.
3. What is the boiling point of nitrogen? A. -210 degrees Celsius B. -196 degrees Celsius C. -182 degrees Celsius D. -150 degrees Celsius
4. What is the color of pure nitrogen gas? A. Blue B. Green C. Colorless D. Red
5. Is nitrogen gas lighter or heavier than air? A. Lighter B. Heavier C. The same D. It depends on the temperature and pressure.
6. What is the solubility of nitrogen in water? A. Highly soluble B. Moderately soluble C. Slightly soluble D. Insoluble
7. Which of the following is a chemical property of nitrogen? A. Odorless B. Colorless C. Reactivity with very electropositive metals D. Slightly soluble in water
8. What is the common name of the process used to produce ammonia from nitrogen and hydrogen gases? A. Haber-Bosch process B. Nitrogen fixation C. Nitrogen cycle D. Nitrogen assimilation
9. Which of the following is a common use of liquid nitrogen? A. Cryogenic freezing B. Fertilizer production C. Food packaging D. Welding
10. Which of the following compounds can be formed by the reaction of nitrogen with oxygen? A. NH3 B. N2O C. HNO3 D. CO2
11. What is the most abundant gas in the Earth’s atmosphere? A. Oxygen B. Nitrogen C. Carbon dioxide D. Methane
12. What physical property of nitrogen allows it to be used as a cooling agent? A. High boiling point B. Low boiling point C. High density D. High viscosity
13. What is the main industrial use of nitrogen gas? A. Food packaging B. Cryogenic cooling C. Fertilizer production D. Welding
14. Which of the following is NOT a common use of liquid nitrogen? A. Cryotherapy B. Superconductors C. Computer cooling D. Food packaging
15. What is the role of nitrogen in food packaging? A. It provides a source of oxygen for the food. B. It helps prevent the growth of bacteria and fungi. C. It adds flavor and aroma to the food. D. It enhances the nutritional value of the food.
16. Which of the following is a medical use of nitrogen gas? A. Production of fertilizers B. Cryotherapy C. Steel production D. Superconductors
17. What is the main component of many fertilizers? A. Oxygen B. Nitrogen C. Carbon dioxide D. Helium
18. What is the Haber-Bosch process used for? A. Production of nitrogen gas B. Production of oxygen gas C. Production of ammonia D. Production of carbon dioxide
19. How is nitrogen used in the steel industry? A. As a coolant B. As a fertilizer C. As a fuel source D. As a reducing agent
20. What is a common use of nitrogen in the electronics industry? A. As a coolant for computer systems B. As a component of batteries C. As a catalyst in chemical reactions D. As a cleaning agent
21. Which of the following is a use of nitrogen in the aviation industry? A. As a fuel source B. As a coolant for engines C. As a component of hydraulic fluid D. As a cleaning agent for aircraft
22. How does nitrogen gas help prevent explosions in certain industrial processes? A. It acts as a catalyst to promote chemical reactions. B. It provides a source of fuel to power the process. C. It displaces oxygen to reduce the risk of fire or explosion. D. It increases the pressure in the process to promote efficiency

The stages in which atmospheric nitrogen is converted into soil nitrogen and back to free nitrogen occurs in the following ways:

1. Oxidation of atmospheric nitrogen: During lightning and thunderstorm, there is electrical discharge in the atmosphere which cause atmospheric nitrogen and oxygen combine to form oxides of nitrogen which can dissolve in rain water as dioxonitrate (III) and trioxonitrate (V) acids. These acids go into the soil and react with mineral salts in the soil to form trioxonitrate (V) salts which is absorbed by plants.N2(g) +  O2(g) 2NO(g)2NO(g)  +  O2(g) 2NO2(g)4NO(g) + O2(g)   +  2H2O(l) 4HNO2(aq)4NO(g) + O2(g)   +  2H2O(l) 4HNO3(aq)
2. Action of nitrogen-fixing bacteria: Soil micro-organisms like Rhizobium living in root nodules of leguminous plants are able to convert atmospheric nitrogen into organic nitrogenous compounds which are used directly by the host plants. These compounds are released into the soil when these plants die. Other free living micro-organisms in the soil like Azotobacter and Clostridium are also able to convert atmospheric nitrogen directly into trioxonitrate (V) which is absorbed by plants. These processes are known as nitrogen fixation.
3. Decay of organic matter: When plants and animal die, putrefying bacteria and fungi in the soil converts organic nitrogenous compounds to ammonia. Nitrifying bacteria like Nitrosomonas and Nitrobacter convert the ammonia to trioxonitrate (V) which can again be absorbed by plants. These processes are known as nitrification.
4. Denitrification: Trioxonitrate (V) salt in the soil can be converted to gaseous nitrogen by denitrifying bacteria. The process is known as Denitrification. The nitrogen so formed escapes into the atmosphere, where it becomes atmospheric nitrogen. Denitrifying bacteria therefore reduces the quantity of trioxonitrate (V) in the soil.  
5. Nitrogen Fixation: Atmospheric nitrogen (N2) is converted into biologically available forms such as ammonia (NH3) and nitrate (NO3-) by certain microorganisms. This can occur through several processes, including biological fixation by nitrogen-fixing bacteria that live in soil or on the roots of certain plants, as well as through industrial processes like the Haber-Bosch process.
6. Nitrification: Ammonia (NH3) is converted into nitrite (NO2-) and then into nitrate (NO3-) by nitrifying bacteria in the soil.
7. Assimilation: Plants and other organisms take up nitrogen in the form of nitrate or ammonium ions from the soil and use it to build organic molecules like amino acids and nucleotides.
8. Ammonification: The decomposition of organic matter by bacteria and fungi releases nitrogen in the form of ammonium ions (NH4+) back into the soil.
9. Denitrification: Certain bacteria in the soil convert nitrate (NO3-) back into atmospheric nitrogen (N2), completing the nitrogen cycle

GENERAL EVALUATION/REVISION

1. Using balanced equation ONLY, show how nitrogen can be prepared in the laboratory.
2. Outline the stages involved in the nitrogen cycle.

1. Write the electronic configuration of N3- and P5-
2. Balance the following redox equation: I–  +  MnO4–  →  IO3–  +  MnO2 in basic medium
3. State the effect of the following on the equilibrium position of the reaction below: 3Fe(s)  +  4H2O(g)             Fe3O4(s)  +  4H2(g)  ∆H = +ve

1. • Increase in temperature
   • Increase in pressure
   • Using iron filings instead of iron rod.

1. Using balanced equation ONLY, show how nitrogen can be prepared in the laboratory. Nitrogen gas (N2) can be prepared in the laboratory by heating ammonium nitrite (NH4NO2) as shown below: NH4NO2(s) → N2(g) + 2H2O(g)
2. Outline the stages involved in the nitrogen cycle. The stages involved in the nitrogen cycle are as follows:

• Nitrogen fixation: atmospheric nitrogen is converted into ammonia or nitrate ions.
• Nitrification: ammonia is converted into nitrite and then into nitrate by nitrifying bacteria.
• Assimilation: plants and animals take up nitrogen in the form of nitrate or ammonium ions from the soil and use it to build organic molecules.
• Ammonification: the decomposition of organic matter by bacteria and fungi releases nitrogen in the form of ammonium ions back into the soil.
• Denitrification: certain bacteria in the soil convert nitrate back into atmospheric nitrogen, completing the cycle.

3. Write the electronic configuration of N3- and P5- N3-: 1s² 2s² 2p⁶ P5-: 1s² 2s² 2p⁶ 3s² 3p⁶
4. Balance the following redox equation: I-  +  MnO4-  →  IO3-  +  MnO2 in basic medium. I- + MnO4- + OH- → IO3- + MnO2 + H2O
5. State the effect of the following on the equilibrium position of the reaction below: 3Fe(s)  +  4H2O(g)  ⇌  Fe3O4(s)  +  4H2(g)  ∆H = +ve

• Increase in temperature: an increase in temperature would shift the equilibrium position to the right, favoring the endothermic reaction, which absorbs heat to form more products.
• Increase in pressure: increasing the pressure would have no effect on the equilibrium position since the number of moles of gas is the same on both sides of the equation.
• Using iron filings instead of iron rod: using iron filings would have no effect on the equilibrium position since the same reactant is being used in both cases

READING ASSIGNMENT

New School Chemistry for Senior Secondary Schools by O. Y. Ababio (6th edition), pages 404-405, 422-423.

WEEKEND ASSIGNMENT

SECTION A :

1. What is the atomic number and symbol for nitrogen?
2. What is the electronic configuration of nitrogen?
3. Name three physical properties of nitrogen.
4. Name two chemical properties of nitrogen.
5. What is the Haber-Bosch process, and how is nitrogen involved in it?
6. What is the nitrogen cycle, and what are its stages?
7. How is nitrogen used in the food industry?
8. What is the main industrial use of liquid nitrogen?
9. What is the chemical equation for the reaction between nitrogen and hydrogen to form ammonia?
10. What is the effect of increasing temperature on the equilibrium position of the reaction 3Fe(s) + 4H2O(g) ⇌ Fe3O4(s) + 4H2(g)?

SECTION B: Write the correct option ONLY

1.  In which group of the periodic table is nitrogen found? (a) 2 (b) 5 (c) 7 (d) 6
2. The boiling point of nitrogen in 0C is (a) -183 (b) -196 (c) 200 (d) 240
3. The percentage of nitrogen in air is (a) 78 (b) 75 (c) 71 (d) 67
4. The following are uses of nitrogen except a. as a cooling agent b. to prevent rancidity c. in the manufacture of fertilizers d. in laundry.
5. The atomicity of nitrogen is (a) 1(b) 2 (c) 3 (d) 4

SECTION B

1. Briefly describe the preparation of nitrogen from air in the laboratory.
2. State three physical properties and two chemical properties of nitrogen.
3. The electronic configuration of N3- is _________.
4. Nitrogen occurs chiefly as a free element in _________.
5. Nitrogen gas is _________ than air.
6. The process used to manufacture ammonia industrially is called the _________ process.
7. Nitrogen can react with non-metals like hydrogen and oxygen to form _________ and nitrogen oxides, respectively.
8. The conversion of atmospheric nitrogen into soil nitrogen and back to free nitrogen is known as the _________ cycle.
9. Liquid nitrogen is commonly used as a cooling agent in various applications, such as cryogenic freezing of food and biological tissues, and in the production of _________.
10. Nitrogen is used as a packaging gas in the food industry to prevent the _________ of packaged foods.
11. The balanced chemical equation for the reaction between nitrogen and hydrogen to form ammonia is N2(g) + _________ → 2NH3(g).
12. Nitrogen is the most abundant gas in the _________

Lesson Plan Presentation: Nitrogen and Its Properties

Grade Level: SS 2

Procedure: Introduction:

1. Begin by asking students if they know what nitrogen is and its importance in the environment.
2. Introduce the topic by defining nitrogen and highlighting its significance in various industries.

Body:

1. Discuss the physical properties of nitrogen, including its color, odor, and density.
2. Explain the chemical properties of nitrogen, including its ability to form compounds with metals and non-metals.
3. Discuss the various uses of nitrogen, including its use in fertilizer production, food packaging, and as a cooling agent.
4. Describe the nitrogen cycle, including its stages and the role of nitrogen in the ecosystem.
5. Use audiovisual aids if necessary to illustrate the concepts discussed.

Activity:

1. Distribute printed copies of review questions and activities to the students.
2. Have students work in groups to answer the questions and complete the activities.
3. Collect the completed activities and review the answers as a class.

Conclusion:

1. Summarize the key points of the lesson.
2. Have students reflect on what they have learned by asking them to share one thing they found interesting or surprising about nitrogen.
3. Encourage students to continue exploring the topic of nitrogen and its properties.

Assessment: Assessment will be based on the student’s ability to answer the review questions and complete the activities. The teacher will review the answers and provide feedback to the students

Weekly Assessment /Test 

1. What is the atomic number of nitrogen? A. 6 B. 7 C. 8 D. 9
2. What is the electronic configuration of nitrogen? A. 1s² 2s² 2p⁵ B. 1s² 2s² 2p³ C. 1s² 2s² 2p⁶ D. 1s² 2s¹
3. Nitrogen gas is: A. Heavier than air B. Lighter than air C. The same density as air D. Cannot be compared with air
4. What is the Haber-Bosch process used for? A. Extraction of nitrogen from air B. Production of liquid nitrogen C. Production of ammonia from nitrogen and hydrogen D. Production of nitrous oxide
5. Which of the following is a chemical property of nitrogen? A. It is odorless B. It is a diatomic gas C. It combines with metals and non-metals to form a variety of compounds D. It has a boiling point of -196°C
6. The conversion of atmospheric nitrogen into soil nitrogen and back to free nitrogen is known as: A. Nitrogen fixation B. Nitrification C. Assimilation D. Nitrogen cycle
7. What is the main industrial use of liquid nitrogen? A. Food packaging B. Cryogenic cooling C. Fertilizer production D. Welding
8. What is the chemical equation for the reaction between nitrogen and hydrogen to form ammonia? A. N2(g) + H2(g) → NH3(g) B. 2NH3(g) → N2(g) + 3H2(g) C. N2O(g) + 2H2(g) → 2NH3(g) D. 2NH4NO3(s) → 2N2(g) + 4H2O(g) + O2(g)
9. Nitrogen is the most abundant gas in: A. The Earth’s atmosphere B. The oceans C. The Earth’s crust D. The human body
10. Liquid nitrogen is commonly used as a cooling agent in: A. Food packaging B. Welding C. Cryogenic freezing D. Steel production