Which among following properties of lanthanoids is NOT true?
Which among following properties of lanthanoids is NOT true?
These are good conductors of heat and electricity
These are strongly paramagnetic
These all are non-radioactive
These have coordination number greater than 6
Solution
The promethium Pm
has an atomic number of 61 . The electronic configuration of promethium is as follows:
$\mathrm{Pm}=[\mathrm{Xe}] 4 \mathrm{f}^5 6 \mathrm{~s}^2$
Promethium (Pm) is the only lanthanide that exhibits radioactivity