The electronic configuration of gadolinium (atomic no. $64$) is

The incorrect relationship in the following pairs in relation to ionisation enthalpies is $:$

Which of the following statements is correct?

Which of the following ions will be colored in an aqueous solution?

Consider $n$ as the number of lone pairs of electrons present in the equatorial position of the most stable structure of $ClF_3$. The ions from the following with $n$ number of unpaired electrons are :
$A. V^{3+}$
$B. Ti^{3+}$
$C. Cu^{2+}$
$D. Ni^{2+}$
$E. Ti^{2+}$
Choose the correct answer from the options given below :

What is enthalpy of atomisation? Explain. $OR$ Write a note on enthalpy of atomisation.