Question

Which of the following are correct?
(i) First ionisation enthalpy of $He<$ Second ionization enthalpy of $Li$.
(ii) $Li$ has the highest second ionisation enthalpy.
(iii) All $d$ - block elements are transition elements.
(iv) The only alphabet not found in the periodic table is the letter ${}^{\prime }{J}^{\prime }$.
(v) Francium concentration is $\sim 10^{-18}ppm$ on Earth.

• A. (i), (ii), (iv)
• B. (i), (ii), (iv), (v)
• C. (i), (ii), (v)
• D. (iv), (v)

Answer 1

Answer: (B)

All transition elements are $d$ - block elements but all $d$ - block elements are not transition metals. A transition metal is one which forms one or more stable ions which have incomplete $d$ - orbitals. On the basis of this definition, scandium and zinc do not count as transition metal although they are $d$ - block elements.