Question

The elements Li(z=3),(Z=11) and K(Z=19) belong to group 1 predict the periods they belong Which one of them has the largest atomic radius? give reason to justify Which one of them is least reactive?

Answer 1

lithium is less reactive
lithium has largest atomic radius
lithium belongs to 2nd period as it has 2 shells
sodium will belong to 3rd period it has 3 shells
potassium will belong to 4th period

Answer 2

Here is your answer:

I) periods of the given elements are:

lithium =2

sodium = 3

potassium=4

II) in the given three elements lithium is least reactive .

--because as we move from top to bottom in a group the reactivity increases so lithium is at the top hence lithium is less reactive than sodium and potassium.

III) potassium would have the largest atomic radius.

---it is because as we move from top to bottom in an group the atomic radius increases due to the addition of new energy shell and hence potassium has the largest atomic radius.

(Lithium has 2 energy shell, sodium has 3 energy shell and potassium has 4 energy cell .)