What is the general electronic configuration of the lanthanides?

Which of the following element belongs to the second transition series of the periodic table?

What is the most common oxidation state of lanthanides?

Which metal is used in making electrical fibres?

The decrease in atomic size of the d-block elements in a series is small after midway.

What is the nature of the transition elements?

Which of the following lanthanide ions do not exhibit color?

Which of the following is used as a nuclear fuel?