MEDIUM
9th CBSE
IMPORTANT
Earn 100

Explain with examples: i. atomic number ii. mass number. Which of these two is the more fundamental property of an element?

Important Questions on Structure of the Atom

MEDIUM
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 2
The nuclear compositions of the atoms X and Y are:
X- protons 7, neutrons 7; Y- protons 9, neutrons 10. Find the mass number of the atoms X and Y.
 
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 3
Define the term nucleon.
HARD
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 4
An element has three electrons in the M shell of its atom. What is the atomic number of the element? 11 / 13
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 5
From the symbol Cl1735 for the element chlorine write down the atomic number and mass number of chlorine.
MEDIUM
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 1
State the valency of aluminium in Al2O3.
MEDIUM
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 2
Out of the elements Cl1735 and, Ar1840, which is chemically more reactive and why?
MEDIUM
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 3
The atomic number of an element is 15. Find the number of valence electrons in its atom. Predict the valency of the element.
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 4 - Structure of the Atom>CHECK YOUR PROGRESS>Q 4

Predict the valency of the following elements: boron (At. No. 5)