English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

Write the full form of IUPAC.

Name the three subatomic particles present in an atom.

What is the usual symbol for (a) and electron (b) a proton, and (c) a neutron?

What are the building blocks of matter ?

How is the size of an atom indicated ?

Name the unit in which the radius of an atom is usually expressed.

Write the relation between nanometre and metre.

Why is it not possible to see an atom even with the most powerful microscope ?

State whether the following statement is true or false :
The cathode rays obtained from all the gases consist of negatively charged particles called electrons.

Fill in the following blanks with suitable words :

In water, the proportion of oxygen and hydrogen is .............. by mass.

How many times is a proton heavier than an electron?

What value has been given to the mass of this reference atom ?

Dalton's atomic theory says that atoms are indivisible. Is this statement still valid ? Give reasons for your answer.

Is it possible to see atoms these days ? Explain your answer.

Name the subatomic particle whose relative charge is : –1

Fill in the blank of the following statement :

Cathode rays are a beam of fast moving _________.

Fill in the blanks of the following statements :

An atom has atomic mass number 23 and atomic number 11. The atom has_________ electrons.

Cathode rays are a beam of fast moving _________

The maximum number of electrons that can be accommodated in L shell are_________

The maximum number of electrons that can go into the M shell is _________

What is an electron? State its relative mass and charge.

What is the absolute mass and charge of an electron?

State two observations which show that atom is not indivisible.