Zinc
Zinc (Zn, atomic number 30) is a Period 4 transition metal (d-block, 65.38 u). Redox-inert Lewis acid cofactor in >300 enzymes—including carbonic anhydrase (hydrating CO₂ at ~10⁶ s⁻¹), RNA polymerase, alcohol dehydrogenase, and structural DNA-binding
Zinc is a chemical element on the periodic table with the atomic symbol Zn, atomic number 30, and standard atomic weight 65.38 u. Classified as a Transition Metal within Group 12 and Period 4 (d-block), zinc possesses a ground-state electron configuration of [Ar] 3d10 4s2 distributed across 4 concentric Bohr electron shells (2 · 8 · 18 · 2) with 2 outer-shell electrons. Redox-inert Lewis acid cofactor in >300 enzymes—including carbonic anhydrase (hydrating CO₂ at ~10⁶ s⁻¹), RNA polymerase, alcohol dehydrogenase, and structural DNA-binding zinc-finger transcription factors.
⚛️ Interactive Periodic Table Lab: Explore Zinc (Zn, Z = 30) in the CRV Science Dynamic Periodic Table & Bohr Orbital Lab to visualize its animated 2 · 8 · 18 · 2 electron shells, simulate live phase transitions from 0 K to 6,000 K, and compare periodic heatmaps across all 118 IUPAC elements.
Atomic Structure and Periodic Trends: How Do Quantum Orbitals Define Zinc?
Electron Shell Architecture and Ground-State Configuration
A neutral atom of zinc contains 30 protons in its atomic nucleus balanced by 30 electrons occupying quantized atomic orbitals. In the Bohr-Sommerfeld and quantum-mechanical orbital models, these electrons populate 4 principal energy shells (K (n=1): 2e−, L (n=2): 8e−, M (n=3): 18e−, N (n=4): 2e−), terminating in the four-lobed d-orbital manifold (azimuthal quantum number l = 2) with ground-state configuration [Ar] 3d10 4s2. Removing the most loosely bound valence electron from an isolated gaseous zinc atom requires a first ionization energy of 906 kJ/mol, while its tendency to attract shared bonding electrons is quantified by a Pauling electronegativity of 1.65.
Periodic Table Position and Neighboring Elements
Within the periodic table, Zinc occupies Period 4, Group 12 of the d-block (Transition Metals). Along Period 4, it is flanked by Copper (Cu, Z = 29) and Gallium (Ga, Z = 31). Vertically within its periodic family, Zinc shares valence orbital symmetry and homologous chemical trends with Cadmium (Cd), Mercury (Hg), Copernicium (Cn). Learners can interactively compare Zinc's orbital radii, ionization energy, and Pauling electronegativity against all neighboring elements in the Dynamic Periodic Table Lab.
Physical and Thermodynamic Properties: How Does Zinc Behave Across Temperature Regimes?
Standard Phase, Melting Point, and Boiling Point Dynamics
At standard ambient temperature and pressure (298.15 K / 25 °C, 1 atm), elemental zinc exists as a crystalline solid. As thermal energy increases, its crystal or molecular lattice undergoes solid-to-liquid fusion at a melting point of 692.68 K (+419.53 °C / +787.2 °F) and transitions to the vapor phase at a normal boiling point of 1,180 K (+906.85 °C / +1664.3 °F), spanning a liquid thermodynamic range of 487.32 K. In the CRV Science Dynamic Periodic Table, dragging the live temperature slider between absolute zero (0 K) and solar-photosphere temperatures (6,000 K) dynamically tracks Zinc's state transitions in real time alongside enthalpy and entropy phase equilibria.
Quantitative Atomic and Thermodynamic Parameter Matrix
| Parameter | Quantitative Value / Formula | Physical / Quantum Basis | Comparative Context in Group 12 / Period 4 |
|---|---|---|---|
| Atomic Number & Symbol | Z = 30 (Zn) | 30 nuclear protons; nuclear charge +30e | Located in Period 4, Group 12 (d-block) |
| Standard Atomic Weight | 65.38 u (g/mol) | Abundance-weighted isotopic nucleon mass | ~35 neutrons in dominant/reference mass number |
| Electron Configuration | [Ar] 3d10 4s2 | Shells: 2 · 8 · 18 · 2 (2 outer-shell e−) | Transition Metals valence orbital architecture |
| Electronegativity & Ionization | χ = 1.65; IE1 = 906 kJ/mol | Pauling bond polarity scale & first valence ionization enthalpy | Governs covalent vs. ionic bond character |
| Melting & Boiling Points | MP: 692.68 K; BP: 1180 K | Cohesive lattice energy and intermolecular forces | STP (298 K) phase: SOLID (Liquid range: 487.32 K) |
| Principal Oxidation States | +2 | Valence electron donation, sharing, or acceptance | Discovered / First Isolated: Ancient |
Chemical Reactivity, Bonding, and Oxidation States: How Does Zinc Form Compounds?
Characteristic Oxidation States and Coordination Chemistry
As a d-block transition metal, partially filled (n−1)d orbitals lie close in energy to the outermost ns subshell, enabling variable oxidation states, d–d electronic transitions, coordination complex formation, and heterogeneous or metalloenzymatic redox catalysis. In chemical compounds, zinc exhibits characteristic oxidation states of +2. Depending on the electronegativity difference (Δχ) of its bonding partners—such as Oxygen (χ = 3.44), Fluorine (χ = 3.98), Chlorine (χ = 3.16), Nitrogen (χ = 3.04), Carbon (χ = 2.55), or Hydrogen (χ = 2.20)—zinc forms redox-specific oxides, halides, hydrides, or coordination complexes governed by Gibbs free energy (ΔG = ΔH − TΔS).
Nucleosynthesis, Discovery History, and Elemental Origins
First identified or isolated in Ancient, Zinc carries a distinct cosmological and geochemical signature. With atomic number Z = 30 beyond the iron-56 binding-energy peak, zinc is synthesized astrophysically via neutron-capture nucleosynthesis—combining slow neutron capture (the s-process in asymptotic giant branch stars) and rapid neutron capture (the r-process in neutron-star mergers and core-collapse supernovae).
Biological Role and Scientific Applications: Why Is Zinc Important in Nature and Technology?
Biochemical Classification: Essential Trace Cofactor
In comparative biochemistry and systems physiology, Zinc is classified as Essential Trace Cofactor. Catalytic transition metal or trace nonmetal required in metalloenzyme active sites (redox catalysis, O2 transport, hormone synthesis). Across terrestrial and marine ecosystems, its chemical speciation interacts with transcription factors, enzymes, electron transport chain, oxidative phosphorylation, reactive oxygen species.
Key Mechanistic Functions and Technological Uses
Redox-inert Lewis acid cofactor in >300 enzymes—including carbonic anhydrase (hydrating CO₂ at ~10⁶ s⁻¹), RNA polymerase, alcohol dehydrogenase, and structural DNA-binding zinc-finger transcription factors. Researchers and students can further investigate Zinc's functional role alongside all 118 elements by launching the Interactive Periodic Table & Element Detective Lab on CRV Science Learn.
Frequently Asked Scientific Questions
What is the electron configuration and valence shell structure of Zinc (Zn)?
Zinc (atomic number Z = 30) has the ground-state electron configuration [Ar] 3d10 4s2, distributing its 30 electrons across 4 shells as 2 · 8 · 18 · 2. Its outermost shell contains 2 electrons, placing Zinc in Group 12, Period 4 (d-block) as a member of the Transition Metals. You can watch these 30 electrons orbit the nucleus in real time in the Dynamic Periodic Table Bohr Lab.
What phase of matter is Zinc at room temperature, and when does it melt or boil?
At standard room temperature (298 K / 25 °C) and 1 atm pressure, Zinc is a crystalline solid. It melts at 692.68 K (+419.53 °C / +787.2 °F) and boils at 1,180 K (+906.85 °C / +1664.3 °F). Using the 0–6,000 K temperature slider in the Interactive Periodic Table, you can observe Zinc's exact solid, liquid, and gas transitions relative to all other elements.
How does Zinc function in biochemistry, materials science, and technology?
Redox-inert Lewis acid cofactor in >300 enzymes—including carbonic anhydrase (hydrating CO₂ at ~10⁶ s⁻¹), RNA polymerase, alcohol dehydrogenase, and structural DNA-binding zinc-finger transcription factors. In biological systems, it is categorized under Essential Trace Cofactor, with principal oxidation states of +2 and a first ionization energy of 906 kJ/mol.