NCERT Class-9 Science Solutions: Chapter 4-Structure of the Atom Part 3 (For CBSE, ICSE, IAS, NET, NRA 2023)
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Question 12:
Elements with valency 1 are
- Always metals
- Always metalloids
- Either metals or non-metals
- Always non-metals
Answer: C
Question 13:
The first model of an atom was given by
- N. Bohr
- E. Goldstein
- Rutherford
- J. J. Thomson
Answer: D
Question 14:
An atom with 3 protons and 4 neutrons will have a valency of
- 3
- 7
- 1
- 4
Answer: C
Question 15:
The electron distribution in an aluminum atom is
Answer: A
Question 16:
Which of the following in Fig, do not represent Bohr՚s model of an atom correctly?
- (i) and (ii)
- (ii) and (iii)
- (ii) and (iv)
- (i) and (iv)
Answer: C
Question 17:
Which of the following statement is always correct?
- An atom has equal number of electrons and protons.
- An atom has equal number of electrons and neutrons.
- An atom has equal number of protons and neutrons.
- An atom has equal number of electrons, protons and neutrons.
Answer: A