Question

Provide the reasons for the following:
(i) Isotopes have different physical properties.
(ii) Hard water is not suitable for washing purposes
(iii) Hydrogen is placed in group first of periodic table
(iv) Ionic compounds have high boiling & melting points
(v) For meteorlogical purposes, hot air is filled into balloons.

Answer 1

Answer:

becoz hard water do not help in fether ......

Answer 2

I) The physical properties of isotopes of the same element are not identical because the atomic mass and mass number of Isotopes differ.

This difference affects physical properties such as density , boiling and melting point etc.

II) Hard water is not suitable for washing clothes because soap doesn't lather with hard water due to the presence of magnesium and calcium salts in hard water.

III) Hydrogen is placed above group in the periodic table because it has ns1 electron configuration like the alkali metals.

But hydrogen has properties similar to both alkali metals and halogens. Thus the position of hydrogen in the periodic table is contradictory.

IV) Ionic compounds have high boiling & melting points because of the presence of strong electrostatic bonds between the opposite charged ions and thus a lot of energy is required to break these bonds.

V) The hot air balloons are filled with gases that are lighter than air mainly helium or hydrogen . These gases allow balloons to float in the air and reach high altitude.

These balloons helps to gather information about humidity , temperature , CO2 level ,ozone level etc.