Question

Which of the following pairs of elements is called chemical twins?
(a) Y-La (b) Fe-Rh c) No-Ta
(d) Ti-ZT​

Answer 1

Answer:

the answer is c according to the question

Answer 2

Option C is the correct answer.

• As the term implies, chemical twins are those elements in which the properties of some ingredients are the same.
• They are a pair of elements possessing identical properties due to identical atomic radii are named chemical twins and they are d-block elements of the 5th and 6th period or 4d series and 5d series. These elements are Zr and Hf, Nb and Ta, Mo and W, Tc, and Re. This consequence occurs due to the lanthanide contraction.
• The reason for the chemical twins is lanthanide compression. The atomic size or the ionic radii of tri-positive lanthanide ions reduce steadily from La to Lu due to boosting nuclear charge and electrons arriving at the inner (n-2)f orbital.
• This gradual reduction in the size with an increasing atomic number is named lanthanide contraction.

Hence, option C is the correct answer.