Chlorine
DIATOMIC NONMETAL
Bohr Model: Electrons arranged in energy shells around the nucleus.
Chlorine is a chemical element with symbol Cl and atomic number 17. It also has a relative atomic mass of 35.5. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine.
Quick Facts
Atomic Number 17
Period 3
Group 17
Phase Gas
Appearance pale yellow-green gas
About Diatomic Nonmetals
Diatomic nonmetals naturally exist as molecules of two atoms (e.g., O₂, N₂). They are typically gases at room temperature.
History
Discovered By Carl Wilhelm Scheele
Named By Unknown
Physical Properties
Atomic Mass 35.45
Density 3.2 g/L
Molar Heat N/A J/(mol·K)
Phase Transition (Melting & Boiling Points)
Chlorine melts at 171.6 K and boils at 239.11 K.
Atomic Properties
Electron Config [Ne] 3s2 3p5
Electronegativity 3.16
Electron Affinity 348.575 kJ/mol
Ionization Energy 1251.2 kJ/mol
Orbital Filling Diagram
This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule.
Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down.
Electrons fill lower energy levels first and occupy orbitals singly before pairing.
Emission Spectrum
Photograph
External Resources
Study Guide
Atomic Number
The number of protons in the nucleus, which defines the element.
Atomic Mass
The average mass of an atom, including protons and neutrons.
Electronegativity
A measure of how strongly an atom attracts electrons in a bond.
Ionization Energy
The energy required to remove an electron from an atom.
Electron Config
The arrangement of electrons in the atom's energy shells.