Transition Metals: Period 4

The first row of transition metals spans from scandium (Sc) to zinc (Zn) in period 4. These ten elements are among the most familiar and industrially important in the entire periodic table. They are characterised by partially filled d-orbitals, which give rise to their distinctive properties.

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Defining Characteristics of Transition Metals

Transition metals share several key properties that distinguish them from the s-block metals:

• Multiple oxidation states — they can form ions with different charges (e.g. Fe²⁺ and Fe³⁺)
• Coloured compounds — due to d-d electron transitions when light is absorbed
• Catalytic activity — many serve as catalysts in industrial and biological processes
• High melting and boiling points — strong metallic bonding due to d-electron involvement
• High density — closely packed atomic structures
• Formation of complex ions — they bond with ligands to form coordination compounds
• Magnetic properties — many are paramagnetic due to unpaired d-electrons

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Period 4 Transition Metals

Element	Symbol	Atomic Number	Common Oxidation States	Electron Configuration
Scandium	Sc	21	+3	[Ar] 3d¹ 4s²
Titanium	Ti	22	+2, +3, +4	[Ar] 3d² 4s²
Vanadium	V	23	+2, +3, +4, +5	[Ar] 3d³ 4s²
Chromium	Cr	24	+2, +3, +6	[Ar] 3d⁵ 4s¹
Manganese	Mn	25	+2, +3, +4, +7	[Ar] 3d⁵ 4s²
Iron	Fe	26	+2, +3	[Ar] 3d⁶ 4s²
Cobalt	Co	27	+2, +3	[Ar] 3d⁷ 4s²
Nickel	Ni	28	+2, +3	[Ar] 3d⁸ 4s²
Copper	Cu	29	+1, +2	[Ar] 3d¹⁰ 4s¹
Zinc	Zn	30	+2	[Ar] 3d¹⁰ 4s²

Note that chromium and copper have irregular electron configurations — they adopt half-filled or fully filled d-subshells for extra stability.

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Element-by-Element Guide

Scandium (Sc, Z = 21)

• Silvery-white metal, relatively soft and light for a transition metal
• Almost always found in the +3 oxidation state
• Used in aluminium-scandium alloys for aerospace components and sports equipment (bicycle frames, baseball bats)
• Scandium oxide is used in high-intensity stadium lighting

Titanium (Ti, Z = 22)

• Strong, lightweight, and highly corrosion-resistant
• Named after the Titans of Greek mythology
• Used extensively in aerospace (jet engines, airframes), medical implants (hip and knee replacements), and sporting goods
• Titanium dioxide (TiO₂) is the world's most widely used white pigment — found in paint, toothpaste, and sunscreen

Vanadium (V, Z = 23)