1: Which Greek goddess is the element Selenium named after?
A: Hera
B: Athena
C: Selene
D: Artemis
Correct Answer: C
Explanation: Selenium is named after Selene, the Greek goddess of the moon, reflecting its connection to tellurium, which is named after the Earth.
2: What is the atomic number of Selenium?
A: 8
B: 16
C: 34
D: 56
Correct Answer: C
Explanation: Selenium has atomic number 34, placing it as the 34th element in the periodic table.
3: In which year was Selenium discovered?
A: 1717
B: 1817
C: 1917
D: 2017
Correct Answer: B
Explanation: Selenium was discovered in 1817 by Jöns Jacob Berzelius and Johann Gottlieb Gahn.
4: What is the most stable form of Selenium at room temperature?
A: Red
B: Yellow
C: Gray
D: Black
Correct Answer: C
Explanation: The most stable and dense form of Selenium at room temperature is gray.
5: Selenium belongs to which group in the periodic table?
A: Group 14
B: Group 16
C: Group 18
D: Group 20
Correct Answer: B
Explanation: Selenium is in group 16 of the periodic table, also known as the chalcogens.
6: What is the primary oxidation state of Selenium in its compounds?
A: +2
B: +4
C: +6
D: -2
Correct Answer: D
Explanation: Selenium commonly exists in oxidation states -2, +4, and +6 in its chemical compounds.
7: Which country is known for producing the most commercial Selenium?
A: Germany
B: Japan
C: USA
D: China
Correct Answer: A
Explanation: Germany is a leading producer of Selenium, contributing significantly to global production.
8: What is Selenium primarily used for in the glass industry?
A: Dyeing glass reddish color
B: Enhancing clarity
C: Making scratch-resistant surfaces
D: Strengthening glass
Correct Answer: A
Explanation: Selenium is used in the glass industry to dye glass a red color, which cancels out undesired tints from impurities.
9: What is the main biological function of Selenium in humans?
A: Bone strengthening
B: Antioxidant support
C: Muscle growth
D: Hydration
Correct Answer: B
Explanation: Selenium plays a crucial role in antioxidant support through involvement in enzymes like glutathione peroxidase.
10: Selenium deficiency can lead to which thyroid condition?
A: Hyperthyroidism
B: Hashimoto’s disease
C: Graves’ disease
D: Goiter
Correct Answer: B
Explanation: Selenium deficiency may exacerbate Hashimoto’s disease, an autoimmune condition affecting the thyroid.
11: In which type of batteries can Selenium be found as an alternative material?
A: Alkaline
B: Lithium-Ion
C: Lithium-Sulfur
D: Nickel-Cadmium
Correct Answer: C
Explanation: Lithium-Selenium batteries are an alternative to lithium-sulfur systems, with advantages in electrical conductivity.
12: Selenium is used in which application for enhanced imaging quality?
A: MRI
B: Ultrasound
C: X-ray detectors
D: Sonography
Correct Answer: C
Explanation: Selenium is used in flat-panel X-ray detectors for high-quality imaging due to its favorable properties.
13: Selenium forms various compounds. Which of these is a common compound of Selenium?
A: Selenium dioxide
B: Selenium chloride
C: Selenium nitrate
D: Selenium phosphate
Correct Answer: A
Explanation: Selenium dioxide (SeO2) is a common Selenium compound, used in various industrial applications.
14: Which allotrope of Selenium is known for its irregular and complex structure?
A: Yellow
B: Black
C: Red
D: White
Correct Answer: B
Explanation: Black Selenium has an irregular, complex structure consisting of polymeric rings.
15: How many naturally occurring isotopes of Selenium are there?
A: 3
B: 5
C: 7
D: 9
Correct Answer: C
Explanation: There are seven naturally occurring isotopes of Selenium, with five being stable.
16: Selenium plays a role in which specific type of enzyme responsible for antioxidant defense?
A: Peroxidase
B: Kinase
C: Lyase
D: Amylase
Correct Answer: A
Explanation: Selenium is crucial for the enzyme family glutathione peroxidases, which reduce reactive oxygen species.
17: What is the chemical symbol for Selenium?
A: Sn
B: Sc
C: Se
D: Sl
Correct Answer: C
Explanation: The chemical symbol for Selenium is Se.
18: Which industrial process primarily produces Selenium as a byproduct?
A: Synthetic Polymer Production
B: Electrolytic Metal Refining
C: Crude Oil Extraction
D: Alkaline Battery Manufacturing
Correct Answer: B
Explanation: Selenium is most commonly produced as a byproduct in the electrolytic refining of metals, especially copper.
19: Large doses of Selenium can lead to a toxic condition known as what?
A: Selenomorphosis
B: Selenosis
C: Seleniumitis
D: Selenopathy
Correct Answer: B
Explanation: Excessive Selenium intake can cause selenosis, characterized by symptoms like hair loss and nervous system damage.
20: Selenium compounds are sometimes used in which household product?
A: Shampoos
B: Detergents
C: Toothpaste
D: Floor Cleaners
Correct Answer: A
Explanation: Selenium disulfide, a compound of Selenium, is used in anti-dandruff shampoos.
21: Which notable scientist discovered Selenium?
A: Albert Einstein
B: Marie Curie
C: Jöns Jacob Berzelius
D: Dmitri Mendeleev
Correct Answer: C
Explanation: Selenium was discovered by the chemist Jöns Jacob Berzelius.
22: What is the melting point of Selenium in Kelvin?
A: 494 K
B: 221 K
C: 373 K
D: 685 K
Correct Answer: A
Explanation: The melting point of Selenium is 494 Kelvin.
23: Which Selenium compound is used in glassmaking to counteract color tints?
A: Selenium sa
B: Zinc selenide
C: Cadmium selenide
D: Sodium selenite
Correct Answer: D
Explanation: Sodium selenite is used in glass manufacturing to counteract green or yellow tints from iron impurities.
24: Which scientific phenomenon was first observed with Selenium’s properties affecting its conductivity?
A: Photoconductivity
B: Superconductivity
C: Piezoelectricity
D: Thermoelectricity
Correct Answer: A
Explanation: In 1873, it was found that the electrical conductivity of gray Selenium was affected by light, leading to its use in photoconductors.
25: Selenium rectifiers, first developed in the 1930s, were primarily replaced by which technology?
A: Silicon Rectifiers
B: Copper Rectifiers
C: Magnetic Induction
D: Thermionic Valves
Correct Answer: A
Explanation: Selenium rectifiers were largely replaced by more efficient silicon rectifiers in the 1970s.
26: Selenium is commonly found as an impurity in which type of ores?
A: Carbonate Ores
B: Sulfide Ores
C: Oxide Ores
D: Halide Ores
Correct Answer: B
Explanation: Selenium is typically found as a minor component in sulfide ores of various metals.
27: What is the most common isotope of naturally occurring Selenium?
A: 72Se
B: 75Se
C: 80Se
D: 82Se
Correct Answer: C
Explanation: The most abundant isotope of naturally occurring Selenium is 80Se, making up about 49.8% of natural Selenium.
28: Selenium deficiencies in humans primarily affect which bodily system?
A: Skeletal
B: Digestive
C: Immune
D: Endocrine
Correct Answer: D
Explanation: Selenium deficiencies primarily affect the endocrine system, particularly the thyroid gland.
29: Which fabricator created the world’s first thin-film solar cell using Selenium?
A: Nikola Tesla
B: Thomas Edison
C: Charles Fritts
D: George Westinghouse
Correct Answer: C
Explanation: Charles Fritts fabricated the first thin-film solar cell using Selenium in the 1880s.
30: Selenium can be used to enhance which type of battery?
A: Nickel-Metal Hydride
B: Lithium-Ion
C: Lithium-Sulfur
D: Alkaline
Correct Answer: C
Explanation: Selenium is used to enhance lithium-sulfur batteries due to its high electrical conductivity.
31: Which property of Selenium makes it useful for X-ray imaging applications?
A: Thermal Conductivity
B: Photoconductivity
C: Electrical Resistance
D: Solubility
Correct Answer: B
Explanation: Selenium’s photoconductivity makes it useful in X-ray detectors, converting X-ray images to patterns of charge.
32: What is the electron configuration of Selenium?
A: [Ar] 3d10 4s2 4p4
B: [Kr] 4d10 5s1 5p3
C: [Ne] 3s2 3p4
D: [Xe] 4f14 5d10 6s2 6p4
Correct Answer: A
Explanation: The electron configuration of Selenium is [Ar] 3d10 4s2 4p4.
33: Selenium is a byproduct in the production of which major industrial material?
A: Aluminum
B: Copper
C: Steel
D: Titanium
Correct Answer: B
Explanation: Selenium is most commonly produced as a byproduct during the refining of copper.
34: Which allotrope of Selenium is used in photocells due to its semiconductor properties?
A: Yellow Selenium
B: Red Selenium
C: Gray Selenium
D: Black Selenium
Correct Answer: C
Explanation: Gray Selenium is used in photocells owing to its semiconductor properties and photoconductivity.
35: What unusual property does Selenium have in its hexagonal form chains?
A: Photoluminescence
B: Chirality
C: High Optical Density
D: High Magnetic Susceptibility
Correct Answer: B
Explanation: The hexagonal form of Selenium consists of chiral helical chains, which are unique to this allotrope.
36: In which electronic component were Selenium rectifiers extensively used before being replaced?
A: Capacitors
B: Transistors
C: Inductors
D: Diodes
Correct Answer: D
Explanation: Selenium rectifiers were extensively used as diodes until they were replaced by silicon-based diodes.
37: What is the chemical formula for Selenium dioxide, a common oxide of Selenium?
A: Se3O2
B: SeO5
C: SeO2
D: Se2O3
Correct Answer: C
Explanation: Selenium dioxide has the chemical formula SeO2, formed through the combustion of elemental Selenium.
38: Selenium is an ingredient in which type of commonly used product for medicinal purposes?
A: Painkillers
B: Multivitamins
C: Cough Syrups
D: Antihistamines
Correct Answer: B
Explanation: Selenium is commonly included as a trace element in multivitamins and dietary supplements.
39: Historically, which famous inventor utilized Selenium in a groundbreaking communication device?
A: Alexander Graham Bell
B: Thomas Edison
C: Guglielmo Marconi
D: Nikola Tesla
Correct Answer: A
Explanation: Alexander Graham Bell used Selenium in his photophone to transmit sound using light in 1879.
40: The discovery of Selenium’s photoconductivity led to its early use in which technological application?
A: Electric Motors
B: Light Meters
C: Automatic Doors
D: Text Messaging
Correct Answer: B
Explanation: Selenium’s photoconductivity was first exploited in light meters and photometers.
41: What is the byproduct formed along with Selenium when Selenium dioxide decomposes at high temperatures?
A: Hydrogen
B: Oxygen
C: Carbon Dioxide
D: Nitrogen
Correct Answer: B
Explanation: When Selenium dioxide decomposes, it produces Selenium and Oxygen.
42: Selenium salts, such as selenite, are known for which property that impacts its use in supplements?
A: High Solubility
B: Low Toxicity
C: High Toxicity
D: Low Conductivity
Correct Answer: C
Explanation: Selenium salts, like selenite, are highly toxic in small doses, posing a risk of selenosis if not properly dosed.
43: What notable property does gray Selenium exhibit that has found use in semiconductors?
A: Isotropic Conductivity
B: Photoconductivity
C: Thermoconductivity
D: Superconductivity
Correct Answer: B
Explanation: Gray Selenium’s photoconductivity has made it useful in semiconductor applications, such as photocells.
44: Which Selenium compound is known for its use in anti-dandruff shampoos?
A: Sodium selenite
B: Selenium dioxide
C: Selenium disulfide
D: Selenium hexafluoride
Correct Answer: C
Explanation: Selenium disulfide is the compound commonly found in anti-dandruff shampoos, helping to control dandruff.
45: Selenium can form a polymeric solid with what kind of molecular structure?
A: Tetrahedral Network
B: Pyramidal Chains
C: Monomeric Rings
D: Hexagonal Grid
Correct Answer: B
Explanation: Selenium forms a polymeric solid with a pyramidal chain structure, particularly noted in Selenium dioxide.
46: What was the discovery by Willoughby Smith in 1873 involving Selenium?
A: Its fluorescence
B: Its magnetic properties
C: Its photoconductivity
D: Its superconductivity
Correct Answer: C
Explanation: Willoughby Smith discovered Selenium’s photoconductivity, which led to its use in light-sensitive applications.
47: The first commercial Selenium product was developed by which scientist?
A: Marie Curie
B: Albert Einstein
C: Werner Siemens
D: Isaac Newton
Correct Answer: C
Explanation: Werner Siemens developed the first commercial products using Selenium, including the Selenium photoelectric cell, in the mid-1870s.
48: Selenium compounds, when combined with sulfur, are used as what type of chemical agent in fireworks?
A: Oxidizing Agent
B: Reducing Agent
C: Coloring Agent
D: Binding Agent
Correct Answer: B
Explanation: Selenium compounds act as reducing agents in the composition of certain fireworks.
49: Selenium is an antagonist to which element, often reducing toxicity in cases of overexposure?
A: Lead
B: Mercury
C: Arsenic
D: Chromium
Correct Answer: B
Explanation: Selenium can reduce the effects of mercury toxicity by binding to the mercury and forming less toxic compounds.
50: Selenium’s interaction with light makes it suitable for which type of sensor?
A: Pressure Sensor
B: Temperature Sensor
C: Optical Sensor
D: Acoustic Sensor
Correct Answer: C
Explanation: Due to its photoconductivity, Selenium is well-suited for use in optical sensors that detect light variations.
51: Selenium rectifiers have been mostly replaced by what more efficient technology for most applications?
A: Copper Rectifiers
B: Germanium Diodes
C: Silicon Diodes
D: Aluminum Rectifiers
Correct Answer: C
Explanation: Silicon diodes have largely replaced Selenium rectifiers due to their higher efficiency and lower cost.
52: Selenium is a byproduct in the commercial refining of which metal?
A: Zinc
B: Copper
C: Iron
D: Aluminum
Correct Answer: B
Explanation: Selenium is often obtained as a byproduct during the electrolytic refining of copper.
53: Which form of Selenium is used for its semiconducting properties in DC power surge protectors?
A: Red
B: Yellow
C: Black
D: Gray
Correct Answer: D
Explanation: Gray Selenium, due to its semiconducting properties, is used in DC power surge protectors.
54: Which oxidation state of Selenium is mostly used in the production of glass pigments?
A: -2
B: 0
C: +4
D: +6
Correct Answer: D
Explanation: Selenates (Se in +6 oxidation state) are used in glass production to impart desired colors.
55: Selenium’s critical role in which human enzyme protects cells from oxidative damage?
A: Amylase
B: Pepsin
C: Glutathione peroxidase
D: Lipase
Correct Answer: C
Explanation: Selenium is crucial for the activity of glutathione peroxidase, an enzyme that protects cells from oxidative damage.
56: How does Selenium enter freshwater ecosystems from human industrial activities?
A: Airborne Dust
B: Agricultural Runoff
C: Chemical Synthesis
D: Direct Discharge
Correct Answer: B
Explanation: Selenium can enter freshwater ecosystems mainly through agricultural runoff, where it leaches from selenium-rich soils.
57: Selenium’s semiconducting properties were first used in the early development of which technology?
A: Radios
B: Telephones
C: Photocopiers
D: Televisions
Correct Answer: C
Explanation: Selenium’s semiconducting properties were first used in the early development of photocopiers, enhancing image clarity.
58: What negative environmental impact can result from Selenium pollution in water bodies?
A: Increased Salinity
B: Bioaccumulation in Aquatic Life
C: Decreased pH Levels
D: Increased Alkalinity
Correct Answer: B
Explanation: Selenium pollution can lead to bioaccumulation in aquatic life, causing toxic effects up the food chain.
59: What form of Selenium is a toxic gas and poses a significant inhalation hazard?
A: Selenium dioxide
B: Hydrogen selenide
C: Sodium selenite
D: Selenium hexafluoride
Correct Answer: B
Explanation: Hydrogen selenide (H2Se) is a highly toxic, corrosive gas that poses a significant inhalation hazard.
60: SSLitgium batteries are being preferred for which specific property of Selenium?
A: High Density
B: Low Weight
C: High Electrical Conductivity
D: Low Melting Point
Correct Answer: C
Explanation: Selenium’s high electrical conductivity makes it a preferred material for lithium batteries, enhancing their efficiency.