7.
In the modern periodic table, elements are classified on the basis of
Answer : A. atomic number
8.
The element used in lead pencils is
Answer : A. carbon
9.
Mass number of an element represents
Answer : A. Number of protons and neutrons
10.
"The properties of elements are periodic function of their atomic weights" This statement was given by
Answer : C. Mendeleef
11.
Which is neither an element nor a compound?
Answer : C. air
12.
An element has atomic weight 24 and equivalent weight 11.9. Its valency is
Answer : B. 2
