The number of protons, neutrons and electrons in particles A to E are given below :

Particle	Protons	Neutrons	Electrons
A	17	18	17
B	3	4	2
C	18	22	18
D	17	20	17
E	9	10	10

Giving reasons, find a pair of isotopes from the above particles.

Q.

(a) What are isotopes ? Explain by giving an example.

(b) Give one similarity and one difference between a pair of isotopes.

(c) Give the number of protons, neutrons and electrons per atom in the two isotopes of chlorine ${}_{17}{}^{35}\mathrm{Cl}$ and ${}_{17}{}^{37}\mathrm{Cl}$.

Q. Constituents of nucleus of three atoms A, B and C are given below:
A - 90 protons and 148 neutrons
B - 92 protons and 146 neutrons
C - 90 protons and 146 neutrons
Based on the above data, which of these atoms are isotopes.

Q. An element ${}_x{A}^y$ emits $5\alpha$ and $4\beta$ particles to give ${}_{82}{B}^{207}$. The number of protons and neutrons in A are respectively.

Q.

Structures of nuclei of three atoms A, B and C are given below: A has 90 protons and 146 neutrons. B has 92 protons and 146 neutrons. C has 90 protons and 148 neutrons. Based on the above data, A and C are isotopes; B and C are ___.

Q. The three smaller particles present in an atom are
(a) elections, protons, neutrons
(b) electrons, portions, neutrons
(c) electrons, protons, neotrons
(d) electrons, protons, neutrons