Daily Practice Problems
Class 10 Science
Periodic Classification of Elements
daily practice problem

Question 1:

Answer the following questions based on the elements with atomic number 3 to 9:

(a) Name the element with smallest atomic radius.

(b) Name the element which shows maximum valency.

(c) Name the element which is a metalloid.

(d) Name the element which is most electropositive.

(e) Write the chemical formula of the compound formed when the elements of atomic number 6 and 8 react together.


Question 2:

How it can be proved that the basic structure of the Modern Periodic Table is based on the electronic configuration of atoms of different elements?


Question 3:

Electronic configuration of an element is 2, 8, 4. State its Name, group and period number.


Question 4:

Based on the group valency of elements write the molecular formula of the following compounds giving justification for each:

(i) Oxide of first group elements

(ii) Halide of the elements of group thirteen, and

(iii) Compound formed when an element, A of group 2 combines with an element, B of group seventeen.


Question 5:

List any three observations which posed a challenge to Mendeleev’s Periodic Law.


Question 6:

How does the metallic character of elements vary on moving from

(i) left to right in a period,

(ii) from top to bottom in a group of the Modern Periodic Table?

Give reason for your answer.


Question 7:

The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons respectively in their outermost shells. Write the group numbers in which these elements are placed in the Modern Periodic Table. Write the electronic configuration of the atoms of B and D and the molecular formula of the compound formed when B and D combine.


Question 8:

‘‘Atomic number of an element is considered to be a more appropriate parameter than its atomic mass for a chemist.’’ Take the example of the element X (atomic number 13) to justify this statement.


Question 9:

How is the valency of an element determined if its electronic configuration is known? Determine the valency of an element of atomic no. 9.


Question 10:

Given below are some elements of the Modern Periodic Table. Atomic numbers of the elements are given in parentheses: A(4), B(9), C(14), D(19), E(20)

(i) With the help of the electronic configuration, find out which one of the above elements will have one electron in its outermost shell.

(ii) Which two elements belong to the same group? Give reasons for your answer.

(iii) Which one of the above elements belonging to the fourth period has bigger atomic radius and why?


Question 11:

Give the Drawbacks of Newlands law of Octaves. 


Question 12:

Give any two triads given by Dobereiner. (Name of element and their atomic mass)


Question 13:

State Mendeleev’s periodic Law.


Question 14:

In the Modern Periodic Table, which are the metals among the first twenty elements?


Question 15:

Name any four metalloids or semi-metals.


Question 16:

How many elements have been discovered till date? Out of that how many elements are naturally occurring?


Question 17:

Which element has

(a) three shells which are completely filled with electrons?

(b) electronic configuration of 2, 8, 7

(c) total of three shells, with five electrons in its valence shell?


Question 18:

An atom has electronic configuration 2, 8, 3.

(a) What is the atomic number of this element and name of this element?

(b) To which of the following elements would it be chemically similar?

N (7)         B (5)          P (15)          Ar (18)


Question 19:

Name and give symbol of:

i) any four Noble gases/Inert gases.

ii) any four Halogens


Question 20:

State Modern Periodic Law.