Please wait...
1800-212-7858 (Toll Free)
9:00am - 8:00pm IST all days
8104911739
For Business Enquiry

or

Thanks, You will receive a call shortly.
Customer Support

You are very important to us

For any content/service related issues please contact on this toll free number

022-62211530

Mon to Sat - 11 AM to 8 PM

Structure of the Atom CBSE Class 9

Share this:

Structure of the Atom Topics

Full fledge assessment Videos

Video Based Test funda (Please watch the above videos before attempting this assessment)
Question 1/20

Q 1. Which of the following is not explained by Rutherford’s atomic model? 

Solution

The major drawback of Rutherford's model of the atom is that it does not explain the stability of the atom. 

Q 2. According to the Rutherford's model of the atom, which subatomic particle revolved around the nucleus in a circular path? 

Solution

According to Rutherford's model of the atom, electrons revolved around the nucleus in a circular path. 

Q 3. The mass number is the 

Solution

The mass number is the sum of the atomic number and neutrons. 

Q 4. Most alpha particles passed straight through the thin gold foil without any deflection. What did Rutherford conclude from this observation? 

Solution

Most alpha particles passed through the gold foil undeflected because most space inside the atom is empty. 

Q 5. Some alpha particles were deflected by the gold foil through small angles. What did Rutherford conclude about the atom from this observation? 

Solution

Few particles were deflected by the foil through small angles. This indicates that the centre of the atom is positively charged and occupies little space. 

Q 6. The mass number of hydrogen is 

Solution

The mass number of hydrogen is 1. 

Q 7. According to Thomson’s model of the atom, the atom as a whole is 

Solution

According to Thomson’s model of the atom, the atom as a whole iselectrically neutral. 

Q 8. Which of the following is an alpha particle? 

Solution

He2+ is an alpha particle. 

Q 9. The number of protons present in an atom is equal to the 

Solution

The number of protons present in an atom is equal to the number of electrons. 

Q 10. Which subatomic particle is found in the extra-nuclear part according to Rutherford’s atomic model? 

Solution

According to Rutherford's model of an atom, electrons revolve around the nucleus in the extra-nuclear part. 

Q 11. Which of the following isotopes of cobalt is radioactive? 

Solution

The isotope Co60 is radioactive and is used to generate energy. 

Q 12. Sir J. J. Thomson’s model of an atom was similar to 

Solution

Sir J. J. Thomson’s model of an atom was similar to Christmas pudding or plum cake with raisins or the cross section of a watermelon. 

Q 13. The Father of Nuclear Chemistry and Nuclear Physics is 

Solution

The Father of Nuclear Chemistry and Nuclear Physics is Ernest Rutherford. 

Q 14. Both protons and neutrons are found in the nucleus; hence, they are collectively known as 

Solution

Both protons and neutrons are found in the nucleus; hence, they are collectively known as nucleons. 

Q 15. Whose model of the atom was similar to the Solar System? 

Solution

Rutherford's model of the atom is similar to the Solar System. The electrons revolve around the nucleus in well-defined orbits. 

Q 16. The entire mass of an atom is concentrated in the 

Solution

The entire mass of an atom is concentrated in the nucleus. 

Q 17. The mass of an atom is determined by the summation of 

Solution

The mass of an atom is determined by protons and neutrons. 

Q 18. Which of the following noble gases does not have an octet? 

Solution

Helium gas has 2 electrons in its outermost shell; hence, it has a duplet. 

Q 19. The nucleus of an atom is 

Solution

The nucleus is dense, positively charged and the centre of an atom. 

Q 20. The maximum number of electrons present in the L shell is 

Solution

The L shell has a maximum of 8 electrons. 

Still have doubt?

Structure of the Atom Notes

Revision Notes

Read CBSE Class 9 Chemistry revision notes for Structure of the Atom

Read Full Notes

`

Structure of the Atom Tests

Structure of the Atom Textbook Solutions

Structure of the Atom Doubts and Solutions

Asked by aryankhannawithfrnd 7th March 2019, 7:02 AM
Asked by ms5838107 7th January 2019, 8:05 PM
Ask question
(*jpeg, png format only)

Chat with us on WhatsApp