Question 1 :-
The term biosphere refers to
Question 2 :-
The boundary between troposphere and stratosphere is known
as
Question 3 :-
Ozone hole is
Question 4 :-
If an object is present at a distance of 5 km from the
surface of the earth, it is present in
Question 5 :-
The uppermost layer of atmosphere is known as
Question 6 :-
Which of the following determines the identity of a chemical
element?
Question 7 :-
Which of the following particles is positively charged in an
atom?
Question 8 :-
Isotopes of a neutral atom have
Question 9 :-
What is the number of protons in an element with atomic
number 17 and mass number 37?
Question 10 :-
Deuterium is an isotope of a hydrogen atom. It contains
Question 11 :-
Find the number of neutrons in a Zn2+ ion. The mass
number is 70.
Question 12 :-
The number of electrons in a neutral atom represents its
Question 13 :-
Elements having the same atomic number but different mass
numbers are called
Question 14 :-
Which of the following contribute mainly to the mass of an
atom?
Question 15 :-
Two atoms are said to be Isobars if
Question 16 :-
Mass of proton is
Question 17 :-
The mass number of the element is
Question 18 :-
The atomic number of an element is equal to
Question 19 :-
An alpha particle is also known as
Question 20 :-
The octet rule is not valid for the molecule
Question 21 :-
The nature of bonding in CCl4 and CaH2 is