Question

Consider the following elements
20Ca, 8O, 18Ar, 16S, 4Be, 2He
Which of the above elements would you expect to be
(i) very stable?
(ii) in group 2 of the periodic table?
(iii) in group 16 of the periodic table?

Answer 1

Answer:

1.argon

berilium , calcium

3.oxygen, sulphur

Answer 2

Inert gases are all Stable

Explanation:

(i) $Ar_1_8\ and\ He_2$ are very stable elements, as their valance shells are completely filled. They belong to the group of inert or noble gases.

(ii) $Ca_2_0\ and\ Be_a$ are the two elements that belong to group 2 of the periodic table. This is because their valency is 2 and they are electropositive.

(iii) $O_8 (2,6)\ and\ S_1_6$ (2,8,6) are the 16th group Elements of periodic table.

     Group number = Valence shell + 10

                              = 6 + 10 = 16