MCQs of Elements and Compounds

 20 multiple-choice questions (MCQs) on the topic of Elements and Compounds in Basics of Chemistry:

  1. Which of the following is a compound?

    • A) Iron
    • B) Oxygen
    • C) Water
    • D) Gold
    • Answer: C) Water

  2. Which of these statements is true about elements?

    • A) They can be broken down into simpler substances.
    • B) They are made of two or more types of atoms.
    • C) Each element is made up of only one type of atom.
    • D) Elements only exist as gases.
    • Answer: C) Each element is made up of only one type of atom.

  3. Which element is represented by the chemical symbol "O"?

    • A) Gold
    • B) Oxygen
    • C) Osmium
    • D) Oganesson
    • Answer: B) Oxygen

  4. Which of the following is NOT a characteristic of a compound?

    • A) It is made of two or more elements chemically combined.
    • B) It can be separated by physical means.
    • C) It has a fixed ratio of atoms.
    • D) Its properties differ from the properties of its elements.
    • Answer: B) It can be separated by physical means.

  5. What is the smallest unit of a compound?

    • A) Atom
    • B) Molecule
    • C) Ion
    • D) Electron
    • Answer: B) Molecule

  6. Which of the following is an example of a diatomic element?

    • A) Sodium
    • B) Oxygen
    • C) Carbon
    • D) Helium
    • Answer: B) Oxygen

  7. What is the formula of water?

    • A) H₂
    • B) O₂
    • C) H₂O
    • D) HO
    • Answer: C) H₂O

  8. What is the term for a substance that cannot be broken down into simpler substances by chemical means?

    • A) Mixture
    • B) Element
    • C) Compound
    • D) Solution
    • Answer: B) Element

  9. Which of the following represents a mixture rather than a compound?

    • A) CO₂
    • B) H₂O
    • C) Air
    • D) NaCl
    • Answer: C) Air

  10. Which of the following best describes a molecule?

    • A) A single atom of an element
    • B) A group of atoms bonded together
    • C) A mixture of two elements
    • D) A chemical symbol
    • Answer: B) A group of atoms bonded together

  11. Which of the following symbols represents an element?

    • A) Na
    • B) H₂O
    • C) CO₂
    • D) CH₄
    • Answer: A) Na

  12. The element Sodium (Na) is most commonly combined with which element to form table salt?

    • A) Oxygen
    • B) Chlorine
    • C) Carbon
    • D) Hydrogen
    • Answer: B) Chlorine

  13. Which of the following is true about compounds?

    • A) They can be separated by physical means.
    • B) They have properties similar to their component elements.
    • C) They always contain carbon.
    • D) They have a definite composition.
    • Answer: D) They have a definite composition.

  14. Which of the following compounds contains three elements?

    • A) H₂O
    • B) NaCl
    • C) CO₂
    • D) C₆H₁₂O₆
    • Answer: D) C₆H₁₂O₆

  15. What type of bond is typically found between the atoms in a molecule of water?

    • A) Ionic bond
    • B) Covalent bond
    • C) Metallic bond
    • D) Hydrogen bond
    • Answer: B) Covalent bond

  16. Which of the following is NOT an element?

    • A) Hydrogen
    • B) Carbon
    • C) Water
    • D) Nitrogen
    • Answer: C) Water

  17. Which of these compounds is essential for human survival and makes up about 60% of the human body?

    • A) Glucose
    • B) Carbon dioxide
    • C) Water
    • D) Salt
    • Answer: C) Water

  18. How many hydrogen atoms are in one molecule of methane (CH₄)?

    • A) 1
    • B) 2
    • C) 3
    • D) 4
    • Answer: D) 4

  19. Which element has the atomic symbol "Fe"?

    • A) Fluorine
    • B) Iron
    • C) Flerovium
    • D) Francium
    • Answer: B) Iron

  20. In which of the following compounds are the elements bonded in a 1:1 ratio?

    • A) H₂O
    • B) NaCl
    • C) CO₂
    • D) NH₃
    • Answer: B) NaCl


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