Question

Choose from the following: 20Ca, 3Li, 11Na, 10Ne
(a) An element having two shells completely filled with electrons.
(b) Two elements belonging to the same group of the periodic table.​

Answer 1

Answer:

Two shells completely filled with electrons

=> Ca and Ne

Elements belonging to the same group

=> Li and Na

Explanation:

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Answer 2

Answer:

Explanation:

i)  has two shells completely filled with electrons.

ii)  and  are elements belonging to the same group.

Explanation:

i) An element having two shells completely filled with electrons.

To identify the electronic distribution, the electronic configuration of the given elements must be written.

- 2, 8, 8, 2

- 2, 1

- 2, 8, 1

- 2, 8

From the above data it is clear that among the four elements, only Neon has two completely filled shells.

(ii) Two elements belonging to the same group of the periodic table

The following is the list of elements along with the group in which it is present:

Ca - Second group

Li - First group

Na - First group

Ne - Eighteenth group

Thus it is inferred that elements such as Lithium (Li) and Sodium (Na) belong to the same group.