CBSE Class 9 Science Structure of The Atom Worksheet Set D

Read and download free pdf of CBSE Class 9 Science Structure of The Atom Worksheet Set D. Download printable Science Class 9 Worksheets in pdf format, CBSE Class 9 Science Chapter 4 Structure of the Atom Worksheet has been prepared as per the latest syllabus and exam pattern issued by CBSE, NCERT and KVS. Also download free pdf Science Class 9 Assignments and practice them daily to get better marks in tests and exams for Class 9. Free chapter wise worksheets with answers have been designed by Class 9 teachers as per latest examination pattern

Chapter 4 Structure of the Atom Science Worksheet for Class 9

Class 9 Science students should refer to the following printable worksheet in Pdf in Class 9. This test paper with questions and solutions for Class 9 Science will be very useful for tests and exams and help you to score better marks

Class 9 Science Chapter 4 Structure of the Atom Worksheet Pdf

SENIOR SECTION

DEPARTMENT OF CHEMISTRY

CLASS IX

STRUCTURE OF ATOM

WORKSHEET- IV
 
1 Mark Questions:
 
1i.. On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole?
 
ii. Where are electrons found in the atom?
 
iii. What are canal rays?
 
iv. Why is the nucleus of an atom positively charged?
 
v. Why did Rutherford select a gold foil in his α-ray scattering experiment?
 
vi. If Mg2+ has 12 protons and 12 neutrons, what is its atomic number and mass number?
 
vii. What is the defect of Rutherford's atom model?
 
viii. Define valency & give one example of a monovalent element.
 
ix. An atom of an element has 7 electrons in its L-shell, name the element and write it's atomic number?
 
x. Why Mg atom gets 2+ charge when it loses two electrons ?
 
xi. Name the particles which determine the mass of an atom.
 
xii. Which of the following are isotopes and which are isobars? Argon, Protium, Calcium, Deuterium
 
2 Marks Questions:
 
2i.. a) Calculate the average atomic mass of chlorine if it exists in two isotopes 35Cl ( 75%) and 37Cl (25%).
 
b) Write the main drawback of Rutherford model of the atom.
 
ii. What are alpha particles? How are they related to Helium gas?
 
iii. State the characteristics of nucleus of an atom.
 
iv. Describe Bohr’s model of the atom?
 
v. The atomic number of chlorine is 17 and mass number is 35.
 
a. What would be the electronic configuration of a negatively charged chloride ion, Cl- ?
 
b. What would be the atomic number and mass number of Cl- ?
 
vi. What is electronic configuration and how is the valency of an atom related to it ?
 
vii. Which of the two would be chemically more reactive element, X of atomic number 18 or Y of atomic number 17 &why?
 
viii. What are isotopes? Why do isotopes show similar chemical properties but they differ in physical properties?
 
ix. Write isotopes of uranium and its uses.
 
x. Write one pair of Isobars. Why the chemical properties of isobars are not similar?
 
3 Marks Questions:
 
3i.. Explain Rutherford's gold foil experiment with diagram.
 
 ii. Write two points of difference between isotopes and isobars.
 
iii. The average atomic mass of a sample of an element ‘X’ is 16.2u. What is the percentage of each isotope 16X and 18X in the sample?
 
iv. Define valency of an element. Find the valency of chlorine and magnesium.
 
v. What is the similarity in the electronic structure of the following set of atoms?
 
Lithium, Sodium & Potassium.Which of the above element is most reactive and why?
 
vi. Complete the following table. Element At. No. Mass

CBSE Class 9 Science Structure of The Atom Worksheet Set D 1



vii. Give reason for the following
 
a) An atom is electrically neutral
 
b) Noble gases show least reactivity
 
c) Nucleus of an atom is heavy and positively charged.
 
d) Ions are more stable than atoms.
 
viii. An element has an atomic number 12 and mass number 26.Draw a diagram showing thedistribution of electrons in the orbits and the nuclear composition of the neutral atom. If thiselement X combines with another element Y whose electronic configuration is 2,8,7, what will be the formula of the compound thus formed?
 
ix. Name the Scientists who have contributed the following towards the understanding of the atomic structure.
 
a) Discovery of electrons
 
b) Canal rays
 
c) Concept of nucleus
 
d) Stationary orbits
 
e) Indivisibility of atoms
 
f) Neutron
 
x. Write the distribution of electrons in an atom of an element whose atomic number is
 
18.What is special about the outermost shell of an atom in this element?
 
xi. State the observations in alpha particle scattering experiment which led to Rutherford making the following conclusions.
 
a) Most of the space in atom is empty.
 
b) Whole mass of atom is concentrated in its centre.
 
c) Centre is positively charged.
 
xii. Explain with examples :
 
a) Atomic number
 
b) Mass Number
 
c) Isotopes
 
d) Isobars
 
xiii. Give any two uses of isotopes.
 
xiv. Define Electronic configuration.
 
xv. Compare the properties of electrons ,protons and neutrons.
 
Multiple choice questions: 
 
i)An ion of an element has three positive charges. The mass number of atom of the element is 27 and the number of neutrons in the atom is 14. The number of electrons in the ion is:
 
a) 13 b) 10 c)14 d)16
 
ii) Isotopes of an element contain:
 
a) Same number of neutrons but different number of protons.
 
b) Same number of neutrons but different number of electrons.
 
c) Different number of protons as well as different number of neutrons.
 
d) Different number of neutrons but same number of protons.
 
iii) The atomic numbers of four elements A , B , C and D are 12, 13 , 15 & 3 respectively.
 
The element which cannot form a cation is :
 
a) A       b) B           c) C           d) D
 
iv) Which of the following is the correct electronic distribution of magnesium ion?
 
a) 2,8       b)2,8,4        c)2,8, 8           d) 2 , 8 , 7
 
Assertion-Reason questions :  
 
The questions below consist of statement of an assertion and a reason. Choose the correct option.
 
(a) If both Assertion and Reason are true and Reason is the correct explanation ofnAssertion.
 
(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
 
c) If Assertion is correct but Reason is incorrect
 
d) If Assertion is incorrect , but reason is correct
 
i) Assertion: 35Cl17 and 37Cl17 are called isotopes of chlorine.
 
Reason: Isotopes of an element have same mass number but different atomic numbers.
 
ii) Assertion: Neon is considered as an inert element.
 
Reason: It has a stable electronic configuration of 2,8.
 
iii) Assertion: Nucleus of an atom is positively charged.
 
Reason: Nucleus is the central part of the atom at which almost the entire mass is concentrated.


Please click on below link to download CBSE Class 9 Science Structure of The Atom Worksheet Set D

Chapter 4 Structure of the Atom CBSE Class 9 Science Worksheet

The above practice worksheet for Chapter 4 Structure of the Atom has been designed as per the current syllabus for Class 9 Science released by CBSE. Students studying in Class 9 can easily download in Pdf format and practice the questions and answers given in the above practice worksheet for Class 9 Science on a daily basis. All the latest practice worksheets with solutions have been developed for Science by referring to the most important and regularly asked topics that the students should learn and practice to get better scores in their examinations. Studiestoday is the best portal for Printable Worksheets for Class 9 Science students to get all the latest study material free of cost. Teachers of studiestoday have referred to the NCERT book for Class 9 Science to develop the Science Class 9 worksheet. After solving the questions given in the practice sheet which have been developed as per the latest course books also refer to the NCERT solutions for Class 9 Science designed by our teachers. After solving these you should also refer to Class 9 Science MCQ Test for the same chapter. We have also provided a lot of other Worksheets for Class 9 Science which you can use to further make yourself better in Science.

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