Question

a) The following table represents the elements and their atomic numbers. With reference to

this, answer the following using only the alphabets given in the table. [3]

ELEMENT ATOMIC NUMBER

X 13

Y 18

Z 7

i. Which element combines with hydrogen to form a basic gas?

ii. Which element has an electron affinity zero?

iii. Which element forms an amphoteric oxide with oxygen?​

Answer 1

Given:

ELEMENT         ATOMIC NUMBER

X                        13

Y                        18

Z                         7

To Find:

i. Which element combines with hydrogen to form a basic gas?

ii. Which element has an electron affinity zero?

iii. Which element forms an amphoteric oxide with oxygen?

Solution:

From the periodic table we find,

X ( atomic number 13)--> Aluminium

Y ( atomic number 18)--> Argon

Z ( atomic number 7)--> Nitrogen

i) Nitrogen reacts with Hydrogen to form Ammonia, a basic gas:

          N₂+3H₂ --> 2NH₃

  Ans: Z(Nitrogen)  

ii) Ideal gases have zero electron affinity.

  Ans: Y(Argon)

iii)Aluminium reacts with oxygen to form aluminium oxide

      4Al+ 3O₂ --> 2Al₂O₃

 Aluminium is an amphoteric oxide i.e., these oxides react with both acids and bases to form salt and water.

Ans: X(Aluminium)