Q1. What is the atomic number of carbon?
a) 5
b) 6
c) 7
d) 8
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Correct Answer: b) 6
Explanation: The atomic number of an element represents the number of protons in its nucleus. Carbon, a fundamental element in chemistry, has an atomic number of 6. This means a carbon atom contains 6 protons in its nucleus. The atomic number determines an element’s chemical properties and its position in the periodic table. Carbon is unique due to its ability to form long chains and complex structures, making it essential for life and the basis of organic chemistry.
Q2. Which of the following is a noble gas?
a) Hydrogen
b) Helium
c) Oxygen
d) Nitrogen
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Correct Answer: b) Helium
Explanation: Noble gases are a group of chemical elements characterized by their extremely low reactivity. They are found in group 18 of the periodic table and include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Helium, with atomic number 2, is the first noble gas and is known for its use in balloons, airships, and cryogenic applications due to its non-flammable and inert nature.
Q3. What is the chemical symbol for iron?
a) Fe
b) I
c) Ir
d) In
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Correct Answer: a) Fe
Explanation: The chemical symbol for iron is Fe, derived from its Latin name “ferrum.” Iron is a transition metal with atomic number 26 and is one of the most abundant elements on Earth. It has various applications, including the production of steel, construction materials, and industrial machinery. The symbol Fe is commonly used in chemical equations and represents one of the essential elements in inorganic chemistry.
Q4. What is the formula of sodium chloride?
a) NaCO3
b) NaCl
c) NaOH
d) Na2CO3
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Correct Answer: b) NaCl
Explanation: Sodium chloride, commonly known as table salt, has the chemical formula NaCl. It is composed of sodium ions (Na+) and chloride ions (Cl-) in a 1:1 ratio. Sodium chloride is a vital compound with numerous applications, including food seasoning, chemical manufacturing, and water treatment. Its simple composition and widespread availability make it a fundamental substance in inorganic chemistry.
Q5. Which element has the highest electronegativity?
a) Hydrogen
b) Oxygen
c) Fluorine
d) Nitrogen
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Correct Answer: c) Fluorine
Explanation: Electronegativity is a measure of an element’s ability to attract electrons in a chemical bond. Fluorine, with the highest electronegativity value of 3.98 on the Pauling scale, is the most electronegative element. It has a strong tendency to attract electrons, making it highly reactive and capable of forming stable compounds with various elements. Fluorine’s electronegativity plays a crucial role in understanding chemical bonding and reactivity in inorganic chemistry.
Q6. Which of the following is not a halogen?
a) Fluorine
b) Chlorine
c) Bromine
d) Mercury
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Correct Answer: d) Mercury
Explanation: Halogens are a group of chemical elements found in group 17 of the periodic table, including fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Mercury (Hg) is not a halogen; it is a transition metal found in group 12. While it is a liquid at room temperature and exhibits some metallic properties, it does not belong to the halogen group.
Q7. What is the chemical formula for water?
a) H2O2
b) HO
c) H2O
d) H3O+
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Correct Answer: c) H2O
Explanation: Water, a vital compound for life and numerous industrial processes, has the chemical formula H2O. It consists of two hydrogen atoms bonded to one oxygen atom through covalent bonds. Water exhibits various unique properties due to its polar nature, including high surface tension, solvent properties, and the ability to form hydrogen bonds. Its simple chemical formula and abundant presence make it a cornerstone of inorganic chemistry.
Q8. Which element is commonly used in batteries?
a) Lithium
b) Calcium
c) Aluminum
d) Sodium
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Correct Answer: a) Lithium
Explanation: Lithium is commonly used in batteries due to its high energy density, lightweight, and ability to provide long-lasting power. Lithium-ion batteries, in particular, have revolutionized portable electronics, electric vehicles, and renewable energy storage systems. Its chemical properties make lithium an ideal choice for electrochemical applications, highlighting its significance in inorganic chemistry and modern technology.
Q9. What is the chemical symbol for potassium?
a) K
b) Pt
c) Ka
d) Po
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Correct Answer: a) K
Explanation: The chemical symbol for potassium is K, derived from its Latin name “kalium.” Potassium is an alkali metal found in group 1 of the periodic table with atomic number 19. It is highly reactive and is essential for various biological processes in living organisms. Potassium compounds are widely used in fertilizers, food additives, and industrial applications, emphasizing its importance in both inorganic chemistry and everyday life.
Q10. Which of the following is a non-metallic element?
a) Magnesium
b) Silicon
c) Phosphorus
d) Copper
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Correct Answer: c) Phosphorus
Explanation: Phosphorus is a non-metallic element found in group 15 of the periodic table. It exists in several allotropic forms, including white phosphorus, red phosphorus, and black phosphorus, with varying properties and reactivities. Non-metallic elements typically lack metallic luster, are poor conductors of heat and electricity, and tend to form acidic or covalent compounds. Phosphorus compounds are essential in fertilizers, detergents, and various industrial processes, contributing to its significance in inorganic chemistry.