Choose from the following. 6C, 8O, 10Ne, 11Na, 14Si (i) Elements that should be in the same period. (ii) Elements that should be in the...

Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order? Give reason. Answer - Noble...

Identify and name the metals out of the following elements whose electronic configurations are given below. (i) 2, 8, 2 (ii) 2, 8, 1...

What is atomic radius? Why does atomic radius decrease across a period? Answer – Atomic radius is defined as the distance from the center...

Give reasons: (i) The elements of group 18 are called zero valent. (ii) Group 17 elements form uninegative anions. Answer – (i) Group 18...

What do you understand by the term periodicity? Does the periodicity in properties is a function of valence electrons? Illustrate. Answer...

Name the element which is in (i) First group and third period (ii) Seventeenth group and second period. Answer - (i) Sodium (ii) Fluorine

Arrange the following elements in the increasing order of their metallic character Mg, Ca, K Answer - Mg < Ca < K

If an element X is placed in group 14, what will be the formula and the nature of bonding of its chloride? [CBSE 2019] Answer - The...

Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev. Answer – GeCl4, GaCl3

How many vertical columns are there in the Modern Periodic Table? Answer - In the Modern Periodic Table, there are 18 vertical columns of...

Define groups. Answer - The vertical columns in the long form of the Periodic Table are called groups.

What was the drawback of the Law of Octaves? Answer - Law of Octaves failed to assign the position to the elements with large atomic...

State Newlands' Law of Octaves. Answer - Newlands' Law of Octaves states that "when elements are arranged in order of increasing atomic...

State Mendeleev's Periodic Law. [CBSE 2019] Answer - Mendeleev's Periodic Law states that, "The physical and chemical properties of the...

What was Dobereiner's basis of classifying elements? Answer - According to Dobereiner, elements having similar properties can be arranged...

Explain why, the direction of induced current in the coil of an A.C. generator changes after every half revolution of the coil. Solution....

A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is : (i) pushed into the coil ? (ii)...

Name two safety measures commonly used in domestic electric circuits and appliances. (NCERT Book Question) Answer. (i) Provision of...

What precautions should be taken to avoid overloading of domestic electric circuits ? (NCERT Book Question) Answer. (i) Too many high...