Which of the following is the correct order of arrangement of the first five lanthanides according to atomic number?

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

The main factor for the cause of lanthanide contraction is poorer shielding of 5d electrons by 4f electrons.

Among d-block elements, the most abundant element belongs to the first transition state.

What is the general electronic configuration of d-block elements?

How many series’ of transition elements are present in the periodic table?

Which isotope of plutonium is used in nuclear bombs?

What is the oxidation state exhibited by actinium?