The number of electrons in an atom is equal to the number of

1. protons in a neutral atom
2. neutrons in a neutral atom
3. nucleons in a neutral atom
4. none of the above

The sum of number of protons and number of neutrons present in the nucleus of an atom is called its

1. mass number
2. atomic number
3. valency
4. none of these

Assertion (A): Matter consists of very small particles called atoms.

Reason (R): Atoms are indivisible.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): An atom is electrically neutral.

Reason (R): The number of protons and the number of electrons are equal in an atom.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.