Question

(i) Sponge is a solid, yet we are able to compress it. Why?

(ii) What are isotopes and isobars?

(iii) What are the characteristics of drugs?

Answer 1

(i) Sponge has very small holes throughout its structure. These holes are filled with air. When it is compressed, the air in the holes is squeezed out. Thus, we are able to compress it.

(ii) Isotopes: The atoms which posses same atomic number (the atoms same element) but a different mass number are called Isotopes.
Ex: ₁H¹, ₁H², ₁H³
These are the isotopes of Hydrogen.
The difference in mass number is due to a different number of neutrons present in the nucleus.
Isobars: The atoms which posses different atomic number with a same mass number are called Isobars.
Ex : ₁₈Ar⁴⁰, ₂₀Ca⁴⁰

(iii) A drug must possess the following characteristics:

1. It should not be toxic.

2. It should not cause any side effects.

3. It should not affect the receptor tissues.

4. It should not affect normal physiological activities.