Atoms and molecules are the fundamental building blocks of matter. Atoms and molecules make up all matter. Atoms contain smaller particles known as subatomic particles, which include electrons, protons, and neutrons. The number of electrons, protons, and neutrons in atoms of different elements varies.
Download Class 9 Chemistry Worksheet on Chapter 4 Structure of the Atom Set 3 PDF
CBSE Class 9 Chemistry Chapter 4 Structure of the Atom Worksheet β Set 3
Q-1: A unit charge monoatomic anion contains 74 neutrons and 54 electrons. Find the atomic number, mass number, and identification of the ion.
Q-2: Except for one exception, neutrons can be found in all atomic nuclei. Which is this atomic nucleus and what does it consist of?
Q-3: Name the subatomic particle whose relative charge is (a) +1 (b) -1 (c) 0.
Q-4: In Rutherford’s experiment, thin foils of heavy atoms such as gold, platinum, and others were bombarded by πΆ-particles.What difference would there be between the above results if a thin foil of atoms such as aluminium was used?
Q-5: Why do electrons present around an atom’s nucleus not fall into the nucleus?
Q-6: Why are the atomic masses the average values?
Q-7: Bohr’s theory does not apply to which of the following species?
a) Li2+
b) He2+
c) H
d) Be3+
Q-8: A neutral atom of element has 2K, 8L and 4M electrons. Find out the following:
a) Atomic number of the element
b) Name of the element
c) Number of neutrons in the nucleus
d) Valency of the element
Q-9: Give one example of each of the following:
i) Isotope of 714N
ii) Isobar of 714N
iii) Isotone of 146C
Q-10: Electron was discovered by
a) Arrhenius
b) J.J. Thomson
c) Michael Faraday
d) Neils Bohr
Q-11: Which subatomic particle was missing from Thomson’s model of the atom?
a) electron
b) proton
c) neutron
d) All of the above
Q-12: Which of the following atom characteristics is not a direct result of Rutherford’s experiment?
a) The atom’s extraordinary hollow nature
b) the existence of circular electronic orbits
c) the nucleus’s small size
d) the nucleus’s exceptionally high density
Q-13: The smallest part of an element that retains the element’s chemical properties is
a) electron
b) proton
c) an atom
d) molecule
Q-14: Which of the following statements about the properties of cathode rays is false?
a) The nature of the gas present in the cathode ray tube determines the characteristics of cathode rays.
b) The characteristics of cathode rays are unaffected by the material of the electrode in the cathode ray tube.
c) In the absence of an external electrical or magnetic field, they travel in a straight line.
d) They begin at the cathode and work their way to the anode.
Q-15: A compound is made up of two elements, X and Y, with X accounting for 80% and Y accounting for 20%. Their moles in the compound are 1.30 and 1.98, respectively. Determine the atomic masses of elements X and Y.
Q-16: Is the law of constant composition true for the compounds obtained from different isotopes of the same element?
Q-17: The electronic configuration of a metallic ion M2+ is 2,8,14, and the ionic weight is 56 amu. The total number of neutrons and protons is
a) 30,26
b) 32,24
c) 34,22
d) 42,14
Q-18: Which of the following pairs contains two species that are both isoelectronic and isotopic? Atomic numbers: Ca=20, Ar=18, Mg=12, Fe=26, Na=11.
a) 40Ca2+ and 40Ar
b) 57Fe3+ and 56Fe2+
c) 23Na+ and 24Na+
d) 24Mg2+ and 25Mg
Q-19: According to Bohr, if the atomic shells are complete then the atom will be
a) more reactive
b) less stable
c) less reactive
d) canβt be predicted
Q-20: Consider the electronic configurations:
i) 2,8,1
ii)2,8,0,1
Answer the following questions:
a) What is the element that corresponds to i)?
b) Is ii) the same or a different element?
c) How is ii) obtained from i)?
d) Is it easier to extract one electron from ii) or i)? Explain.
Download the PDF to access answers to the Chemistry Worksheet for Class 9 Chemistry Chapter 4 Structure of the Atom Set -3
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Read Also:
- Atoms and Molecules
- Rutherfordβs Atomic Model and Limitations
- Thomsonβs Atomic Model
- Thomsonβs Atomic Model and its Limitations
- Class 9 Structure of the Atom MCQ
- Class 9 Structure of the Atom Important Questions with Answers
- Chemistry Concept Questions and Answers
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