d-block and f-block Elements — Flashcards

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Transition elements are those which have partially filled d-orbitals either in their atomic state or in any of their common oxidation states. For example, Fe (Z=26) has electronic configuration [Ar] 3…

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Copper forms Cu²⁺ ion with configuration [Ar] 3d⁹ — partially filled d-orbital. Zinc forms Zn²⁺ with [Ar] 3d¹⁰ — fully filled d-orbital. Since transition elements must have partially filled d-orbitals…

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The general electronic configuration of d-block elements is (n-1)d¹⁻¹⁰ ns¹⁻², where n is the principal quantum number of the outermost shell.

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Chromium (Cr, Z=24) has configuration [Ar] 3d⁵ 4s¹ instead of 3d⁴ 4s² because half-filled d-subshell (d⁵) is more stable. Copper (Cu, Z=29) has [Ar] 3d¹⁰ 4s¹ instead of 3d⁹ 4s² because fully filled d¹…

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Fe (Z=26): [Ar] 3d⁶ 4s². On ionization, electrons are removed from 4s first, then 3d. Fe²⁺: [Ar] 3d⁶ Fe³⁺: [Ar] 3d⁵…

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Due to strong metallic bonding caused by small atomic size and involvement of unpaired d-electrons in bonding. More unpaired electrons → stronger bonding → higher melting point.

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As we move left to right, nuclear charge increases. d-electrons shield poorly, so effective nuclear charge increases, pulling electrons closer and decreasing atomic size.

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The steady decrease in atomic and ionic radii of lanthanides from La to Lu due to poor shielding by 4f electrons. As nuclear charge increases, 4f electrons do not shield effectively, causing contracti…