MEDIUM
10th CBSE
IMPORTANT
Earn 100

The atomic numbers of three elements A, B and C are given below:
Element Atomic Number
A 11
B 13
C 18
(i) Which element belongs to group 1?
(ii) Which element belongs to group 13?
(iii) Which element belongs to group 18?
(iv) To which period do these elements belong?

Important Questions on Periodic Classification of Elements

MEDIUM
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 13
An element X is in group 13 of the periodic table :
(i) What is the valency of X?
(ii) What will be the formula of its oxide?
(iii) What will be the formula of its chloride?
MEDIUM
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 14
An element A has an atomic number of 8, another element B has atomic number 12:
(a) In which group of the periodic table would you expect to find these elements?
(b) What type of bond is formed between A and B?
(c) Suggest a formula of the compound formed between A and B.
MEDIUM
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 14

The atom of an element (M) has electronic configuration 2, 8, 3:
(a) What is the atomic number of this element?
(b) To which group of the periodic table does it belong?
(c) To which of the following elements would it be chemically similar?
     B(5), Mg(12), C(6), N(7)

MEDIUM
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 15
The general outer electronic configuration of noble gas is ns2np6. Helium, however has 1s2 configuration, rest of the inert gases have 8 electrons in their outermost valence shell. This imparts stability to the atoms of these gases. As a result of which they neither lose nor gain electrons. Consequently these gases are almost chemically inert.
Read the above passage and answer the following questions:
(i) Write the names and symbols of the elements of group 18.
(ii) Why are inert gas also called noble gases?
(iii) Neon is generally used for warning signals. Why?
MEDIUM
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 16
Mendeleev predicted the existence of two elements and named them as Eka-Silicon and Eka-Boron.
(a) Name the elements which took over their positions.
(b) Name the groups to which these elements belong and also give their electronic configuration.
(c) Predict the valencies of these elements.
EASY
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 17
Hydrogen is regarded as a rogue element in the periodic table. Elaborate.
MEDIUM
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 17
What is the usual number of valence electrons and valency of group 18 elements of the periodic table?
EASY
10th CBSE
IMPORTANT
NEW ERA CHEMISTRY Textbook for Class X>Chapter 5 - Periodic Classification of Elements>MOCK TEST>Q 17
Which has a bigger size, argon or chlorine. Explain why?