Question

97]
16. Which is the correct order of ionic sizes (At. No.: Ce
= 58, Sn - 50. Yh 70 and Lu=71) TAIEEE 2002]
(a) Ce > Sn> Yb Lu (b) Sn > Ce > La > Y
(c) La > Y > S > Ce (d) Sn > Yb > Ce > Lu​

Answer 1

Lu<Yb<Ce<La<Sn

Ionic size decreases with increase in atomic number i.e Lu has the smallest radii in the above series due to lanthanide contraction. Sn (Tin) does not fall ynder lanthanide series.

Answer 2

Correct increasing order of ionic sizes is as follows.

$Sn^{2+}$ < $Ce^{3+}$ < $Yb^{3+}$ < $Lu^{3+}$  

Explanation:

Higher is the atomic number of an atom larger will be its size. As atomic number is the number of protons present in an atom. And, for a neutral atom the number of protons equal to the number of electrons present in the atom.

Smaller is the positive charge on an ion larger will be its size.

For the given elements, Ce forms a $Ce^{3+}$ ion and has 55 electrons.

Sn forms $Sn^{2+}$ ion and it has 48 electrons. Yb forms $Yb^{3+}$ ion and it has 67 electrons. Whereas Lu forms $Lu^{3+}$ ion so it has 68 electrons.

Hence, correct increasing order of ionic sizes is as follows.

$Sn^{2+}$ < $Ce^{3+}$ < $Yb^{3+}$ < $Lu^{3+}$  

Learn more about ionic size:

https://brainly.in/question/8458796

https://brainly.in/question/13393089

#Learnwithbrainly