Question

why are metals like sodium potassium and lithium soft in nature unlike other metals?

Answer 1

Lithium is light mainly because it has a low atomic mass and low density. In general, pure samples of metals get heavier as their atomic mass gets heavier, and lithium has the lowest atomic mass of all the metals. Also, all groups on the periodic table get heavier as you go down the column

Sodium or Na has periodic number: 11 and group 1 and period 3. Na or Sodium is usually regarded as a soft metal as it is verysoft and can be cut using a knife. K (Potassium) is also regarded as a soft metal. Because it is an alkali metal which has just one valance electron so the metallic bonds are not very strong

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