MEDIUM
10th CBSE
IMPORTANT
Earn 100

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

MEDIUM
10th CBSE
IMPORTANT
Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 11
What is the difference between valence electrons and valency of an element? Discuss with an example.
MEDIUM
10th CBSE
IMPORTANT
Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 12
Sodium and aluminium have atomic numbers 11 and 13 respectively. They are separated by one element in the periodic table and have valencies 1 and 3 respectively. Chlorine and potassium are also separated by one element in the periodic table. Their atomic numbers are 17 and 19 respectively, but both have a valency of 1. Explain why
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
IMPORTANT
Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 16
Explain the term ionization energy. Mention the units in which they are measured. How do they generally vary (i) in a group and (ii) in a period?
HARD
10th CBSE
IMPORTANT
Foundation Science Chemistry FOR CLASS 10>Chapter 1 - Periodic Classification of Elements>EXERCISES>Q 16
Explain the term electron affinity. Mention the units in which they are measured. How do they generally vary (i) in a group and (ii) in a period?