HARD
10th CBSE
IMPORTANT
Earn 100

Two elements M and N belong to groups I and II respectively and are in the same period of the periodic table. How do the following properties of M and N vary?
(i) Sizes of their atoms                          (ii) Their metallic characters
(iii) Their valencies in forming oxides    (iv) Molecular formulae of their chlorides

Important Questions on Periodic Classification Of Elements

MEDIUM
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 3

The elements of the second period of the periodic table are given below:

Li Be B C N O F
(a) Give reason to explain why atomic radii decreases from Li to F.
(b) Identify the most (i) metallic and (ii) non-metallic element.

HARD
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 5

Elements have been arranged in the following sequence on the basis of their increasing atomic masses.

F, Na, Mg, Al, Si, P, S, CI, Ar, K

(a) Pick two sets of elements that have similar properties.
(b) The given sequence represents what law of classification of elements?

HARD
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 6
Three elements A, B and C have 3, 4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the modern periodic table. Also, give their valencies.
HARD
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 1
H               He
Li Be   B C N O F Ne
Na Mg   Al Si P S CI Ar

Using the above table explains why:
(i) Li and Na are considered as active metals.
(ii) Atomic size of magnesium is less than sodium.
(iii) Fluorine is more reactive than chlorine.
MEDIUM
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 2
What is meant by periodicity in properties of elements with reference to the periodic table.
EASY
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 2
Why do all elements in a same group have similar properties?
MEDIUM
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 2
How will the tendency to gain electrons changes as we go from left to right across a period and why?
HARD
10th CBSE
IMPORTANT
Core Science Chemistry>Chapter 5 - Periodic Classification Of Elements>EXERCISE 5C>Q 3
The position of three elements A, B and C in the periodic table are shown below:

Group VI

Group VII
- -
- A
- -
B C


Giving reasons, for the following:
(a) Element A is a non metal.
(b) Element B has a larger atomic size than element C.
(c) Element C has a valency of 1.