9: Electronic Configurations and Radii of Lanthanum and Lanthanoids
* Only electrons outside [Xe] core are indicated
All the lanthanoids are silvery white soft metals and tarnish rapidly in air The hardness increases with increasing atomic number, samarium being
steel hard Their melting points range between 1000 to 1200 K but
samarium melts at 1623 K They have typical metallic structure and are
good conductors of heat and electricity