Find the value ( x y × z ) , for the given elements. U(92) , Pu(94) , Ce(58) , Eu(63) , Gd(64) , Tb(65) , Pm(61) X = Number of elements which have 1 or 2 electrons in (n – 1)d or (n – 2)f subshell Y

Question

Find the value ( x y × z ​ ) , for the given elements. U(92) , Pu(94) , Ce(58) , Eu(63) , Gd(64) , Tb(65) , Pm(61) X = Number of elements which have 1 or 2 electrons in (n – 1)d or (n – 2)f subshell Y = Number of elements which have zero electrons in (n – 1)d or (n – 2)f subshell Z = Number of radioactive elements

TestHub · Accepted Answer

Question Explanation:

Count elements based on subshell electrons and radioactivity.

Concept:

Electronic configuration of f-block elements.

Solution:

• Consider $(n - 1) d$ and $(n - 2) f$ subshells for each element.

• Ce (58): [Xe] 4f¹ 5d¹ 6s² → has 1 e⁻ → counted in X

• Eu (63): [Xe] 4f⁷ 6s² → neither 1/2 nor 0 → ignored

• Gd (64): [Xe] 4f⁷ 5d¹ 6s² → has 1 e⁻ → counted in X

• Tb (65): [Xe] 4f⁹ 6s² → ignored

• Pm (61): [Xe] 4f⁵ 6s² → ignored

• U (92): [Rn] 5f³ 6d¹ 7s² → has 1 e⁻ → counted in X

• Pu (94): [Rn] 5f⁶ 7s² → ignored

• No element has zero electrons in both required subshells → $Y = 0$

• Radioactive elements: U, Pu, Pm → $Z = 3$

Final Answer: $X = 3$ , $Y = 0$ , $Z = 3$

Chemistry - f-block Question with Solution | TestHub

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