Reactivity & Chemical Bonding
Chemical Behavior & Oxidation States
Selenium exhibits chemical reactivity characteristic of the nonmetal family, governed by an electronegativity of 2.55 and standard valence interactions.
Z = 34Reactive Nonmetal
Launch 3D Atom & Orbitals LabSelenium
Se
Standard Atomic Mass: 78.971 u
Period 4Group 16P-Block
Chemical Specimen/Se
Concentric Electron Shells4 Energy Levels
n=1: 2e⁻→
n=2: 8e⁻→
n=3: 18e⁻→
n=4: 6e⁻
Scientific Monograph • Reactive Nonmetal
3D Atom SimulatorSelenium (Se) Scientific Profile
Selenium (Se) is an element with atomic number 34, classified as a nonmetal. Positioned in Period 4, Group 16, and P-block, its chemical and physical profile is defined by its electron configuration ([Ar]3d¹⁰4s²4p⁴) and periodic trends.
Interactive Virtual Labs Available for Selenium
3D Orbitals & Valence Lab
Simulate concentric quantum energy levels, observe valence electron spins, and examine live atomic clouds in full 3D.
Electronic Configuration Lab
Experiment with Aufbau subshell ordering, explore orbital occupancy, and analyze quantum configuration exceptions.
Electron Config
[Ar]3d¹⁰4s²4p⁴
Electronegativity
2.55 Pauling
Year Discovered
1817
Orbital Shells
4 Principal Levels
Orbital Block
p-block orbital
Group / Period
G: 16 • P: 4
Technological Utility
Industrial & Energy Applications
Selenium is utilized in industrial fabrication, materials engineering, electronic manufacturing, and advanced laboratory research based on its specific thermodynamic properties.
Biological Role
Biomedical Profile & Toxicity
Selenium does not play a prominent biological role in human biochemistry, existing primarily as a trace element or mineral component in natural ecosystems.
Geochemistry & Abundance
Cosmic & Terrestrial Occurrence
Elements like Selenium are synthesized through stellar nucleosynthesis and supernovae r-processes. On Earth, Selenium is concentrated in specific ore deposits or synthesized in nuclear accelerators.
Frequently Asked Questions about Selenium
Q
What are the key physical and atomic properties of Selenium?
Selenium (Se) has an atomic number of 34 and a standard atomic mass of 78.971 u. It is positioned in Period 4, Group 16, in the P-block, and is classified within the Reactive Nonmetal category.
Q
What is the electron configuration of Selenium?
The ground-state electron configuration of Selenium is [Ar]3d¹⁰4s²4p⁴. Its 34 electrons are distributed across 4 principal energy levels (2, 8, 18, 6).
Q
Why does Selenium exhibit an electron configuration exception?
Selenium follows standard Aufbau principle orbital filling. Transition metals and heavy elements optimize their shell filling based on subshell exchange energy and electrostatic stability.
Q
What are the primary commercial and laboratory uses of Selenium?
Selenium is utilized in industrial fabrication, materials engineering, electronic manufacturing, and advanced laboratory research based on its specific thermodynamic properties.