Question

1. If the nucleus of an atom were left undisturbed

Answer 1

Answer:

For 1: The correct answer is C.

For 2: The correct answer is B.

Explanation:

• For 1:

Nucleus of the atom lies in the center of the atom and contains two main subatomic particles which are neutrons and protons.

Neutrons are electrically neutral subatomic particle.

Protons are positively charged subatomic particles.

If the nucleus is unstable then it will undergo decay process and will change into another nucleus otherwise there will be no change in the nucleus if it is left undisturbed for years.

Hence, the correct option is C.

• For 2:

Chemical change is defined as the process in which chemical composition of the substance changes completely and it forms a new substance. They are usually irreversible processes.

Physical change is defined as the process in which only physical properties of the substance changes like state and size ad does not lead to the formation of a new substance. They are usually reversible processes.

When we boil an egg in water using a pan, the egg is undergoing chemical change because in it denaturation of protein is taking place which means that breaking of bond between the amino acids is taking place.

Hence, it is the egg which is undergoing a chemical change. So, the correct option is B.

Answer 2

1. C
Atoms are stable and no change will occur to them if they are left over a period of time.

2. B
The egg's chemical properties change due to the application of heat.