Class 9 NCERT Solutions Structure of the Atom

Class 9 NCERT Solutions Structure of the Atom - NCERT Solutions prepared for CBSE students by the best teachers in Delhi. 

Class IX Science

 Chapter 4 – Structure of the Atom

Question 1:

What are canal rays?

Answer:

Canal rays are positively charged radiations. These rays consist of positively charged

particles known as protons. They were discovered by Goldstein in 1886.

Question 2:

If an atom contains one electron and one proton, will it carry any charge or not?

Answer:

An electron is a negatively charged particle, whereas a proton is a positively charged particle. The magnitude of their charges is equal. Therefore, an atom containing one electron and one proton will not carry any charge. Thus, it will be a neutral atom.

Question 3:

On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole.

Answer:

According to Thomson’s model of the atom, an atom consists of both negatively and positively charged particles. The negatively charged particles are embedded in the positively charged sphere. These negative and positive charges are equal in magnitude. Thus, by counterbalancing each other’s effect, they make an atom neutral.

Question 4:

On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?

Answer:

On the basis of Rutherford's model of an atom, protons (positively-charged particles) are present in the nucleus of an atom.

Question 5:

Name the three sub-atomic particles of an atom.

Answer:

The three sub-atomic particles of an atom are:

(i) Protons

(ii) Electrons, and

(iii) Neutrons

Question 6:

Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?

Answer:

Helium atom has two neutrons. The mass of an atom is the sum of the masses of protons and neutrons present in its nucleus. Since helium atom has two protons,mass contributed by the two protons is (2 × 1) u = 2 u.

 

Students should free download the NCERT solutions and get better marks in exams. Studiestoday.com panel of teachers recommend students to practice questions in NCERT books and download NCERT solutions.

Tags: 

 


Click to View or Download pdf file
Click for more Science Study Material

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

Checking of Boards Answer sheets starts today

CBSE has instructed almost 3000 schools to start the evaluation work for class 10th and class 12th board exam answer sheets from today. The checking of answer sheets for class 10th and class 12th was stopped earlier due to covid crisis in the country. Now in order to...

CBSE Recommends Arogya Setu App

Written recommendation from CBSE to school principals for initiating the Arogya Setu App! The Central Board of Secondary Education has advised to all school principals through a written communication recommending the “Arogya Setu App” and Health Ministry's protocol for...

Procedure for correction in Name and Date of Birth

Procedure for correction in Name and Date of Birth in CBSE records Name Change: Applications regarding changes in name or surname of candidates will be considered provided the changes have been admitted by the Court of law and notified in the Government Gazette before...

Board Exams Class 10 and Class 12 Datesheet 2020

CBSE has announced the datesheet for the remaining exams of class 10 and class 12 exams. The exams are going to start in July. The class 10 and 12th board exams will be conducted for the remaining 29 papers from July 1 to July 15, 2020, at various centers nominated by...

Class 10 and Class 12 Board Exams to be resumed only for Main Subjects

The CBSE Board Exams have been postponed twice this year! New Delhi: The Education Ministry has urged the Central Board of Secondary Education (CBSE) to reinstitute the board exams only for the main subjects. As per the official statement the Board will not conduct...

CBSE Boards Answer Sheet Evaluation Class 10 and Class 12

HRD Minister Ramesh Pokhriyal, through a video conference with all the education ministers of the state, discussed the further steps to be taken to smoothen the education process during the Covid-19 lockdown. The most important topic which was discussed repeatedly on...

×
Studies Today