Write the electronic structures of the atoms of (a) potassium, (b) lithium, (c) fluorine and (d) chlorine. Use these electronic structures to explain why potassium is more reactive than lithium, and fluorine more reactive than chlorine.

Important Questions on Periodic Classification of Elements

EASY

10th CBSE

IMPORTANT

Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q I

The ‘law of octaves’ was enunciated by:

MEDIUM

10th CBSE

IMPORTANT

Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q I

From left to right in a period, the acidic nature of the oxides of elements

HARD

10th CBSE

IMPORTANT

Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 13

The atomic number of an element X is 17. Predict (a) its valency, (b) whether it is a metal or non-metal, (c) the nature of the element, (d) the name of the element, and (e) the relative size with respect to other members of its group.

HARD

10th CBSE

IMPORTANT

Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 14

Two elements X and Y belong to groups I and 2 respectively in the same period. Compare them with respect to (a) the number of electrons in the outermost shell, (b) the number of valence electrons, (c) metallic character, (d) size of the atoms and (e) formula of the oxides, hydrides and chlorides.

MEDIUM

10th CBSE

IMPORTANT

Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 15

Define periodic law. Why was it necessary to change the basis of classification from atomic mass to atomic number?

MEDIUM

10th CBSE

IMPORTANT

Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 16

Explain the term atomic radius. Mention the units in which they are measured. How does this generally vary (i) in a group and (ii) in a period?

HARD

10th CBSE