Enter a player name to begin or load your saved progress.
Silicon is a chemical element characterized by being a soft, malleable solid with a bright metallic sheen.
Answer: False
Explanation: The source material describes silicon as a hard, brittle crystalline solid with a blue-grey metallic lustre, not a soft, malleable one.
Silicon belongs to Group 14 and Period 3 of the periodic table, sharing its group with elements like Carbon and Germanium.
Answer: True
Explanation: Silicon is indeed located in Group 14 and Period 3 of the periodic table, sharing its group with Carbon and Germanium, confirming its classification.
At standard temperature and pressure, silicon exists as a gas with a dull grey appearance.
Answer: False
Explanation: At standard temperature and pressure, silicon exists as a solid with a crystalline structure and metallic lustre, not as a gas.
Silicon's melting and boiling points are relatively low compared to most nonmetals, facilitating its use in low-temperature applications.
Answer: False
Explanation: Silicon possesses high melting and boiling points (1687 °C and 3265 °C, respectively), ranking second only to Boron among metalloids and nonmetals, which contradicts the assertion of them being relatively low.
The electrical conductivity of silicon decreases significantly as its temperature increases, a characteristic of metals.
Answer: False
Explanation: Silicon's electrical conductivity increases with temperature due to its semiconductor nature, characteristic of materials with a small energy gap, not decreases like metals.
Silicon's large band gap energy is the primary reason for its excellent conductivity at room temperature.
Answer: False
Explanation: Silicon's semiconductor behavior stems from its relatively small band gap, which allows thermal energy to excite electrons into the conduction band, enabling conductivity, rather than its large band gap causing excellent conductivity.
Silicon is classified as a p-block element, situated in Group 14 and Period 3.
Answer: True
Explanation: Silicon is correctly classified as a p-block element, situated in Group 14 and Period 3 of the periodic table.
The diamond cubic crystal lattice is the only known allotrope of silicon under any conditions.
Answer: False
Explanation: While diamond cubic is the most common allotrope, silicon can also exist in other forms, such as the BC8 allotrope formed under high pressure.
The most common oxidation state for silicon in compounds is +4.
Answer: True
Explanation: The +4 oxidation state is indeed the most common and stable for silicon in its compounds.
Silicon is classified strictly as a non-metal due to its lack of electrical conductivity.
Answer: False
Explanation: Silicon is classified as a metalloid, exhibiting properties intermediate between metals and non-metals. It functions as a semiconductor, meaning its electrical conductivity can be controlled, rather than lacking conductivity entirely.
Silicon's high melting and boiling points are due to weak intermolecular forces in its crystalline structure.
Answer: False
Explanation: Silicon's high melting and boiling points are a result of strong covalent bonds within its giant crystalline structure, not weak intermolecular forces.
Which of the following best describes silicon's fundamental chemical nature?
Answer: A tetravalent metalloid functioning as a semiconductor.
Explanation: Silicon is chemically characterized as a tetravalent metalloid that functions as a semiconductor, possessing properties intermediate between metals and non-metals.
According to the periodic table information provided, which element is directly above silicon in Group 14?
Answer: Carbon
Explanation: In Group 14 of the periodic table, Carbon is situated directly above Silicon.
How is silicon's appearance described at standard temperature and pressure?
Answer: A hard, crystalline solid with a blue-grey metallic lustre.
Explanation: At standard temperature and pressure, silicon is described as a hard, crystalline solid exhibiting a blue-grey metallic lustre.
Compared to other metalloids and nonmetals, where do silicon's melting and boiling points rank?
Answer: They are the second highest, surpassed only by Boron.
Explanation: Silicon's melting and boiling points are notably high, ranking second only to Boron among metalloids and nonmetals.
Why does silicon's electrical conductivity increase with temperature?
Answer: The small energy gap allows thermal energy to excite electrons into the conduction band.
Explanation: The increase in silicon's electrical conductivity with temperature is attributed to its small energy gap, which permits thermal energy to excite electrons into the conduction band.
What is the primary significance of silicon's band gap?
Answer: It allows silicon to function as a semiconductor when energy is supplied.
Explanation: Silicon's band gap is significant because it enables the material to function as a semiconductor, allowing its conductivity to be controlled by external energy or doping.
Which of the following is a key reason for silicon's classification as a metalloid?
Answer: It exhibits properties intermediate between metals and non-metals.
Explanation: Silicon is classified as a metalloid because its properties are intermediate, falling between those of metals and non-metals.
The standard atomic weight of silicon is precisely 28.085, with no specified range or uncertainty.
Answer: False
Explanation: The standard atomic weight of silicon is given as 28.085, with a range of [28.084, 28.086] provided, indicating there is a specified uncertainty or range.
Naturally occurring silicon consists of only one stable isotope, Silicon-28.
Answer: False
Explanation: Naturally occurring silicon consists of three stable isotopes: Silicon-28, Silicon-29, and Silicon-30, not just one.
Silicon-29 is the only stable isotope useful for NMR spectroscopy due to its nuclear spin of 1/2.
Answer: True
Explanation: Silicon-29 is indeed the only stable isotope with a nuclear spin of 1/2, making it particularly useful for NMR and EPR spectroscopy.
Silicon-32 is the most stable radioactive isotope of silicon, with a half-life measured in milliseconds.
Answer: False
Explanation: Silicon-32 is a radioactive isotope with a half-life of approximately 157 years, not milliseconds. Silicon-31 has a half-life of hours.
Silicon is primarily formed during the silicon-burning stage in the core of massive stars.
Answer: True
Explanation: Silicon is synthesized in massive stars during the silicon-burning stage of stellar nucleosynthesis, contributing to the formation of heavier elements.
What is the approximate range for silicon's standard atomic weight as mentioned in the text?
Answer: [28.084, 28.086]
Explanation: The text provides the standard atomic weight of silicon as 28.085, with an associated range of [28.084, 28.086].
Which of the following is NOT a stable isotope of silicon found naturally?
Answer: Silicon-32
Explanation: Silicon-28, Silicon-29, and Silicon-30 are the three stable isotopes found naturally. Silicon-32 is a radioactive isotope.
What property makes Silicon-29 particularly useful for NMR and EPR spectroscopy?
Answer: It is the only stable isotope with a nuclear spin (I = 1/2).
Explanation: Silicon-29 is uniquely valuable for NMR and EPR spectroscopy because it is the sole stable isotope possessing a nuclear spin of 1/2.
Jöns Jacob Berzelius successfully isolated pure silicon in the 19th century using a method involving molten potassium.
Answer: True
Explanation: Jöns Jacob Berzelius successfully isolated pure silicon in 1823 using a method involving the reduction of potassium fluorosilicate with molten potassium.
Antoine Lavoisier was the first to isolate silicon but failed to recognize it as a distinct element.
Answer: False
Explanation: Antoine Lavoisier correctly identified silica as an oxide but could not isolate the element due to silicon's strong affinity for oxygen, a challenge overcome by Berzelius.
The name 'Silicon' is derived from the Latin word for 'flint' or 'hard stone'.
Answer: True
Explanation: The name 'Silicon' is derived from the Latin words 'silex' or 'silicis,' meaning flint or hard stone.
Silicon's strong affinity for oxygen made its isolation straightforward for early chemists.
Answer: False
Explanation: Silicon's strong affinity for oxygen made its isolation challenging for early chemists, requiring specific reduction methods rather than straightforward isolation.
Russell Ohl's work in the 1940s on silicon led to the discovery of the p-n junction and photovoltaic effects.
Answer: True
Explanation: Russell Ohl's pioneering work in the 1940s on silicon led directly to the discovery of the p-n junction and the photovoltaic effect, foundational for modern electronics.
Which process is mentioned for the first isolation of pure silicon?
Answer: Reduction of potassium fluorosilicate with molten potassium.
Explanation: Jöns Jacob Berzelius first isolated pure silicon in 1823 by reducing potassium fluorosilicate with molten potassium.
Why was Antoine Lavoisier unable to isolate silicon in 1787?
Answer: Silicon's strong chemical affinity for oxygen made reduction difficult.
Explanation: Lavoisier could not isolate silicon because its strong affinity for oxygen made reducing silica challenging with the chemical methods available at that time.
What is the origin of the name 'Silicon'?
Answer: From the Latin 'silex' or 'silicis' meaning 'flint'.
Explanation: The name 'Silicon' originates from the Latin words 'silex' or 'silicis,' which translate to 'flint'.
Russell Ohl's discovery of the p-n junction in silicon was foundational for:
Answer: Modern semiconductor electronics, including diodes and transistors.
Explanation: Russell Ohl's discovery of the p-n junction in silicon laid the groundwork for modern semiconductor electronics, enabling the development of diodes and transistors.
Silicon is the most abundant element by mass in the Earth's crust.
Answer: False
Explanation: Silicon is the second most abundant element by mass in the Earth's crust, after oxygen. It is the eighth most common element in the universe.
Ferrosilicon is an alloy primarily used in the glass manufacturing industry.
Answer: False
Explanation: Ferrosilicon is an alloy of iron and silicon primarily used in the steel and iron industries as a de-oxidizing agent and alloying addition, not in glass manufacturing.
Metallurgical grade silicon has a purity level of at least 99.999%, making it suitable for direct semiconductor use.
Answer: False
Explanation: Metallurgical grade silicon has a purity of 95-99%, significantly lower than the ultra-high purity required for semiconductor applications.
Silicates are compounds primarily containing silicon and nitrogen, forming the basis of many rocks.
Answer: False
Explanation: Silicates are compounds primarily containing silicon and oxygen, forming the basis of most minerals in the Earth's crust, not silicon and nitrogen.
Silicon is the ______ most common element by mass in the universe.
Answer: Eighth
Explanation: Silicon ranks as the eighth most common element by mass throughout the universe.
What is ferrosilicon?
Answer: An alloy of iron and silicon.
Explanation: Ferrosilicon is defined as an alloy composed of iron and silicon.
What purity level characterizes metallurgical grade silicon?
Answer: 95% to 99%
Explanation: Metallurgical grade silicon is characterized by a purity level ranging from 95% to 99%.
Doping silicon with Group 13 elements like Boron creates n-type semiconductors by adding extra electrons.
Answer: False
Explanation: Doping silicon with Group 13 elements (e.g., Boron) creates p-type semiconductors by introducing holes, not n-type semiconductors with extra electrons. N-type semiconductors are formed by doping with Group 15 elements.
A p-n junction allows current to flow equally well in both directions, making it unsuitable for diodes.
Answer: False
Explanation: A p-n junction is designed to allow current to flow predominantly in one direction, a characteristic essential for its function as a diode. It does not allow current to flow equally well in both directions.
Silicon dioxide (SiO₂) is vital in semiconductor technology primarily because it acts as an excellent electrical insulator.
Answer: True
Explanation: Silicon dioxide's role as an excellent electrical insulator is critical for its use in semiconductor manufacturing, enabling the creation of devices like MOSFETs.
The Siemens process is the standard method for producing high-purity monocrystalline silicon for wafers.
Answer: False
Explanation: The Czochralski process is the standard method for producing high-purity monocrystalline silicon for wafers, not the Siemens process.
Silicon quantum dots are valued for their potential applications in displays and sensors due to their tunable optical properties.
Answer: True
Explanation: Silicon quantum dots are valued for their tunable optical properties, which arise from their size-dependent quantum confinement effects, enabling applications in displays and sensors.
Silicon's abundance and the stability of its oxide layer are key factors contributing to its dominance in semiconductor manufacturing.
Answer: True
Explanation: Silicon's abundance, the stability of its oxide layer, and its controllable semiconductor properties are key factors in its dominance in electronics manufacturing.
Extrinsic semiconductors are made by doping pure silicon to significantly alter its electrical conductivity.
Answer: True
Explanation: Extrinsic semiconductors are indeed created by doping pure silicon with impurities to significantly alter its electrical conductivity.
What type of semiconductor is formed when silicon is doped with an element from Group 15 (like Phosphorus)?
Answer: N-type semiconductor
Explanation: Doping silicon with Group 15 elements, such as Phosphorus, results in the formation of an n-type semiconductor due to the introduction of excess electrons.
What is the function of a p-n junction formed in silicon?
Answer: To allow current to flow predominantly in one direction.
Explanation: A p-n junction's primary function is to permit electrical current to flow predominantly in a single direction, which is fundamental to diode operation.
In semiconductor manufacturing, silicon dioxide (SiO₂) is primarily used as:
Answer: An electrical insulator and gate dielectric.
Explanation: Silicon dioxide serves as a crucial electrical insulator and gate dielectric in semiconductor fabrication, facilitating device isolation and control.
The Czochralski process is used to produce what type of silicon?
Answer: High-purity monocrystalline silicon.
Explanation: The Czochralski process is the standard method employed for producing high-purity monocrystalline silicon essential for semiconductor wafers.
Silicon quantum dots are noted for potential applications due to their:
Answer: Size-dependent luminescent properties.
Explanation: Silicon quantum dots are recognized for their potential applications, primarily stemming from their size-dependent luminescent properties.
Why is silicon the dominant material for semiconductor electronics?
Answer: Its oxide layer is an excellent insulator, and its band gap is controllable.
Explanation: Silicon's dominance in semiconductor electronics is due to its favorable band gap, controllable conductivity, and the excellent insulating properties of its oxide layer.
What is the key difference between intrinsic and extrinsic silicon semiconductors?
Answer: Intrinsic silicon is pure; extrinsic silicon is doped with impurities.
Explanation: The fundamental difference lies in purity: intrinsic silicon is pure, whereas extrinsic silicon is intentionally doped with impurities to modify its electrical properties.
Unpurified silicon is primarily used in the manufacturing of high-end computer chips.
Answer: False
Explanation: High-purity silicon is required for manufacturing computer chips. Unpurified or metallurgical grade silicon (95-99% purity) is used for industrial applications like cement, ceramics, and glass.
Adding silicon to aluminum alloys, like silumin, generally decreases their hardness and wear resistance.
Answer: False
Explanation: Adding silicon to aluminum alloys, such as silumin, generally increases their hardness and wear resistance and reduces casting defects.
Silicon's high thermal storage capacity makes it a candidate for energy storage systems, particularly at moderate temperatures.
Answer: False
Explanation: While silicon has thermal storage potential, its primary advantage in this context is its high capacity and efficiency at elevated temperatures, not moderate temperatures.
Before its chemical isolation, silicon-based materials were primarily used for primitive tools.
Answer: False
Explanation: Before its isolation, silicon-based materials like silica were used for applications such as glassmaking and construction mortars, not for primitive tools.
Which of the following is a primary industrial use of silicon in its unpurified form?
Answer: Component in cement, ceramics, and glass.
Explanation: Unpurified silicon is extensively utilized in the production of cement, ceramics, and various types of glass.
How does silicon addition affect aluminum alloys like silumin?
Answer: It enhances hardness and reduces casting defects.
Explanation: The addition of silicon to aluminum alloys, such as silumin, enhances their hardness and wear resistance while mitigating casting defects.
What advantage does silicon offer for thermal energy storage compared to traditional salts?
Answer: Higher storage capacity and efficiency.
Explanation: Silicon offers advantages in thermal energy storage, notably higher storage capacity and efficiency compared to traditional salt-based systems.
Before its isolation, silicon-based materials like silica were used historically for:
Answer: Making glass and decorative items.
Explanation: Historically, before silicon's isolation, materials like silica were utilized for crafting glass and decorative objects.
In plants, silicon strengthens cell walls, improving resistance to pests and diseases.
Answer: True
Explanation: Silicon uptake by plants strengthens their cell walls, providing structural support and enhancing resistance to pests, diseases, and environmental stresses.
Silicon is considered non-essential for human nutrition, with no known biological role.
Answer: False
Explanation: Emerging evidence suggests silicon plays a role in human health, particularly in bone density and connective tissue synthesis, contrary to it being non-essential.
Inhaling fine crystalline silica dust can lead to silicosis, a serious lung disease.
Answer: True
Explanation: Inhaling fine crystalline silica dust is a well-documented cause of silicosis, a serious and potentially fatal occupational lung disease.
Silicosis is a condition caused by silicon's high melting point.
Answer: False
Explanation: Silicosis is a lung disease caused by the inhalation of crystalline silica dust, not by silicon's high melting point.
Diatoms utilize silicon to construct their rigid cell walls, known as frustules.
Answer: True
Explanation: Diatoms utilize silicon to construct their rigid cell walls, known as frustules, which are composed of biogenic silica.
The Southern Ocean is characterized by low diatom productivity, leading to high silicon export.
Answer: False
Explanation: The Southern Ocean is characterized by high diatom productivity, which leads to significant silicon consumption and limits silicon export, creating a 'biogeochemical divide'.
Phytoliths are large, fossilized silicon structures found in ancient geological formations.
Answer: False
Explanation: Phytoliths are microscopic silica structures found within plant tissues, not large fossilized formations.
How does silicon contribute to plant health according to the source?
Answer: By strengthening cell walls against pests and diseases.
Explanation: Silicon contributes to plant health by reinforcing cell walls, thereby enhancing resistance to pests and diseases.
What evidence suggests silicon is important for human health?
Answer: It is linked to better bone density and connective tissue synthesis.
Explanation: Evidence suggests silicon is important for human health, particularly for bone density and the synthesis of connective tissues like collagen and elastin.
What is the main health hazard associated with inhaling crystalline silica dust?
Answer: Silicosis, a lung disease causing inflammation and scarring.
Explanation: The primary health hazard from inhaling crystalline silica dust is silicosis, a debilitating lung disease characterized by inflammation and scarring.
What is the role of diatoms in the ocean's silicon cycle?
Answer: They consume silicon to build their cell walls (frustules).
Explanation: Diatoms play a crucial role by utilizing dissolved silicon to construct their intricate silica cell walls, known as frustules.
The term 'biogeochemical divide' in the context of the Southern Ocean refers to:
Answer: Limited transport of silicon out of the region due to high diatom consumption.
Explanation: The 'biogeochemical divide' in the Southern Ocean signifies the limited export of silicon due to extensive consumption by diatoms within the region.
What are phytoliths?
Answer: Microscopic silicon structures within plant tissues.
Explanation: Phytoliths are microscopic structures composed of silica that are deposited within the tissues of plants.