Argon
Noble GasAtomic Number: 18 • Atomic Mass: 39.9480 u • Period: 3 • Group: 18
Atomic Structure
Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶The electron configuration represents the distribution of electrons in atomic orbitals, showing how they are arranged in energy levels and subshells.
Subatomic Particles
18
Positive charge
22
No charge
18
Negative charge
Atomic Number & Mass Number
The atomic number (18) represents the number of protons in the nucleus.
The mass number (40) is the sum of protons and neutrons in the nucleus.
Isotopes
Isotopes are variants of an element that have the same number of protons but different numbers of neutrons.
³⁶Ar
³⁸Ar
⁴⁰Ar
Stability & Half-Life
Half-Life Information
All natural isotopes are stable
Half-life is the time required for half of the atoms of a radioactive isotope to decay.
Periodic Table Location
Period: 3
Group: 18
Category: Noble Gas
The period indicates the main energy level, while the group suggests similar chemical properties.