Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
AP EAMCET201823 Apr 2018Morning ShiftChemistryClassification of Elements and Periodicity in PropertiesActual

In lanthanides, with increase in atomic number atomic radius decreases, except for the element X . What is X ?

Options

  1. AGd
  2. BEu
  3. CTm
  4. DDy

Correct answer

B. Eu

Step-by-step solution

Lanthanides show decrease in atomic radius with increase in atomic number since electrons are filled in the f -subshell. Since, the f -subshell after poor shielding, the atomic size will decrease as the nuclear charge increases. Eu electronic configuration is 4 f^7, 6 s^2 with half-filled outermost shell so nuclear pull is less and it does not show lanthanide contraction.

Practice Classification of Elements and Periodicity in Properties on Quantrex Academy →

More from Classification of Elements and Periodicity in Properties

Which of the following is an INCORRECT match? 2026Match List-I with List-II: List-I (Element-Atomic number) List-II (Position in periodic table) (a) Ra – 88 (i) 4^ th period, 13^ th group (b) Ga – 31 (ii) 6^ th period, 6^ th group 2026Which element from following has positive electron gain enthalpy? 2026Which of the following elements belongs to group 2 and sixth period of periodic table? 2026Identify the most electronegative element by the following. 2026Identify increasing order of acidity for following diprotic acids in aqueous solutions. 2026Identify the group of periodic table that contains element Astatine. 2026What happens to the size of atoms in p-block elements when we move from left to right in the same period? 2026 Full Classification of Elements and Periodicity in Properties list All AP EAMCET PYQs