Assertion :The emission of $\alpha$-particles results in the formation of isodiapheres of parent element. Reason: Isodiapheres have same isotopic number.

Q. Assertion: The compressibility factor for $H_2$​ and $He$ is $(1+\frac{Pb}{RT})$
Reason: The compressibility factor for $H_2$​ and $He$ can be derived from Van der Waal's equation.

Q.

Assertion: The mass of Chlorine is 35.5 u

Reason: For elements having isotopes, the average of mass of its isotopes is considered as the atomic mass of that element.

Q.

Assertion (A) All collision of reactant molecules lead to product formation.

Reason (R) Only those collisions in which molecules have correct orientation and sufficient kinetic energy lead to compound formation.

(a) Both assertion and reason are correct and the reason is correct explanation of assertion
(b) Both assertion and reason are correct, but reason does not explain assertion.
(c) Assertion is correct, but reason is incorrect
(d) Both assertion and reason are incorrect
(e) Assertion is incorrect but reason is correct.

Q.

Assertion: Be and Al have similar properties.

Reason: $B{e}^{2+}$ and $A{l}^{3+}$ have nearly the same charge/volume ratios and similar polarising power.

Q. Assertion : Two electrons of helium atom are placed in only one shell but three electrons of lithium need two shells.
Reason: A shell can have maximum ${\text{2n}}^2$ electrons.