An element has the electron configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d1. Which block of the periodic table does this element belong to?
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Correct answer
C. d-block
Principle or equation
The block of an element is determined by the subshell that receives the last electron according to the Aufbau principle. For transition metals, the last electron enters a d subshell.
Why this answer is correct
The configuration ends with 6d1, meaning the last electron is added to the 6d subshell. Elements with partially filled d orbitals are d-block elements (transition metals).
Example
Scandium (Sc) has configuration [Ar] 3d1 4s2; it is a d-block element.
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