Diamond and Emerald are composed of which of the following respectively?

Which of the following metals exists in a liquid state during the summer season?

Explain briefly how the $+2$ oxidation state becomes more stable in the first half of the first-row transition elements as the atomic number increases.

Explain the variations in atomic radii of transition elements in a group.

Although Zirconium belongs to the $4d$ transition series and Hafnium to the $5d$ transition series,they show similar physical and chemical properties because . . . . . . .

Which transition metal configuration exhibits the highest oxidation state?