7. Which of the following is not a lanthanide property? a) They are soft metals with white silvery colour b) They tarnish rapidly by air c) The hardness of the metals increases with increase in the atomic number d) The melting point of the metal ranges from 500-1000K
Answer: d Explanation: Lanthanides are soft metals that are silvery white in appearance. They discolour quickly when exposed to air. As the atomic number of these metals rises, so does their ability to be harnessed. Lanthanides have melting points ranging from 1000 to 1200 degrees Celsius, whereas samarium melts at 1623 degrees Celsius.
