Give the number of neutrons in an atom of the element A g 47 107 .

The atomic number of Ag = 47 The atomic mass of Ag = 107 u The number of neutrons can be calculated as: Neutrons (n) = Mass number−Atomic number n = 107 - 47 = 60 The number of neutrons in an atom of element A g 47 107 is ⇒ 60 .

How are the following pairs of atoms related? X 16 , 8 X 8 17 , Y 40 18 Z 40 , 20

Elements X 16 8 and X 8 17 are isotopes. In isotopes, the elements have the same atomic number, but the mass number is different. It means the number of protons are the same in both the elements and differ by number of neutrons. Elements Y 40 18 and Z 40 20 are isobars. In isobars, the elements have the same mass number, but differ by the atomic number. It means number of protons are different.

E M B I B E

All In One SCIENCE CBSE Class IX>Chapter 4 - Structure of the Atom>CHAPTER EXERCISE>Q 7

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9th CBSE

IMPORTANT

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In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).
Assertion: Bohr's orbits are called stationary orbits.
Reason: Electrons remain stationary in these orbits for some time.
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Important Questions on Structure of the Atom

EASY

9th CBSE

IMPORTANT

All In One SCIENCE CBSE Class IX>Chapter 4 - Structure of the Atom>CHAPTER EXERCISE>Q 8

In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).
Assertion According to Bohr's model, the orbits of an atom are also called energy levels.
Reason Orbits are the spheres containing the definite value of energy.
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