Periodic Classification of Elements | Class 10 | Activity 5.4 with Solution

Periodic Classification of Elements | Activities in Text Book with Solution

Activity 5.4

Look at the group 1 of the Modern Periodic Table, and name the elements present in it.

✅ Answer: Group 1 elements: Hydrogen (H), Lithium (Li), Sodium (Na), Potassium (k), Rubidium (Rb), Cesium (Cs) and Francium (Fr).

Write down the electronic configuration of the first three elements of group 1.

✅ Answer: (i) Hydrogen: 1    (ii) Lithium: 2, 1    (iii) Sodium: 2, 8, 1

What similarity do you find in their electronic configurations?

✅ Answer: They have same number of valence electrons, i.e. 1.

How many valence electrons are present in these three elements?

✅ Answer: 1

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