Alpha particles are essentially: MCQ with Answer and Explanation

Alpha particles are essentially:
A. Photons
B. Hydrogen atoms
C. Helium nuclei
D. Electrons
Answer: Option C
Solution (By JKExamLibrary)
Alpha particles (α) are positively charged particles consisting of two protons and two neutrons, identical to the nucleus of a helium-4 atom (He²⁺). They are emitted during alpha decay of heavy radioactive elements like uranium and radium.

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Practice More chemistry Questions

Question #1
Alpha particles are identical to the nucleus of:
A. Lithium
B. Hydrogen
C. Deuterium
D. Helium

Correct Answer: Option D


Explanation:
An alpha particle (α) consists of 2 protons and 2 neutrons, which is the same as a helium-4 nucleus (²⁴He²⁺). It has a +2 charge. Beta particles are electrons (β⁻) or positrons (β⁺). Gamma rays are electromagnetic waves with no mass or charge. Alpha particles have low penetration power and are stopped by a sheet of paper or skin. Rutherford used alpha particles in his scattering experiment.

This question belongs to: Science chemistry
Question #2
Which of the following water purification methods can remove dissolved salts?
A. Reverse osmosis
B. Chlorination
C. Ozonation
D. Filtration

Correct Answer: Option A


Explanation:
Reverse osmosis uses a semipermeable membrane to reject dissolved salts and impurities. Filtration removes solids; chlorination/ozonation disinfect but do not remove salts.

This question belongs to: Science chemistry
Question #3
Assertion (A): Zinc can displace copper from copper sulfate solution. Reason (R): Zinc is more reactive than copper.
A. A is false but R is true.
B. Both A and R are true but R is NOT the correct explanation of A.
C. A is true but R is false.
D. Both A and R are true and R is the correct explanation of A.

Correct Answer: Option D


Explanation:
In the electrochemical series, zinc is placed above copper, meaning it has a higher oxidation potential (is more reactive). A more reactive metal can displace a less reactive metal from its aqueous salt solution. Therefore, zinc displaces copper from CuSO4, forming ZnSO4 and depositing Cu metal. R correctly explains A.

This question belongs to: Science chemistry