Question

Inorganic chemistry
Topic :- Periodic table​

Answer 1

Outer configuration for different blocks:

• s-block : $\ ns^{1-2}$
• p-block : $\ ns^2 np^{1-6}$

From above observations:

• A,B,C,D belongs to p-block.
• E belongs to s-block.

》E is eliminated as for same group, the element should belong to same block.

★Condition for belonging to same group:

• elements should belong to same block.
• ★★ elements should have same outer valence configuration.

From above points we can say,

• A and B has same outer EC ,i.e, ns²np²
• They both belongs to p-block and 14th group(10+no. of electron in valence shell).
• A = 2nd period, B= 3rd period.

while C belongs to group 15th and D from 16th.

so, A and B belongs to same group.

Answer 2

★ Question:

Elements A to E have the following configuration:

A: [He] 2s² 2p²

B: [Ne] 3s² 3p⁴

C: [Ne] 3s² 3p³

D: [Ne] 3s² 3p⁴

E: [Ar] 4s²

Which of the above will belong to the same group in the periodic table?

★ Answer:

Elements A and B will belong to the same group.

★ Explanation:

Before proceeding with this question, let's understand the concept.

❀ Concept used:

• For elements to belong to the same group, the number of valence electrons in their electronic configuration must be equal.

In this question, let us find out the number of valence electrons for each element.

Element A:

If p orbital contained 6 electrons, then it would have been completely filled.

Here, there are only 2 electrons.

So, Number of valence electrons = 6 - 2 = 4

Element B:

Similar to element A this element has 2 electrons in its p-orbital.

So, Number of valence electrons = 4

Element C:

Number of valence electrons = 6 - 3 = 3

Element D:

Number of valence electrons = 6 - 4 = 2

Element E:

s-orbital can hold a maximum of 2 electrons.

This element is Calcium.

Number of valence electrons = 2

But this element in s-block. So it's eliminated.

Now, as it can be observed elements A and B have 4 valence electrons.

∴ Elements A and B belong to the same group.