Arsenic

Chaitra 26/06/2026 19:58:08 Updated 26/06/2026 19:58:08

Property	Value
Atomic Number	33
Element	Arsenic
Symbol	As
Atomic Mass	74.922 u
Number of Neutrons	42 (most common isotope, Arsenic-75)
Number of Protons	33
Number of Electrons	33
Period	4
Group	15
Phase	Solid
Radioactive	No
Natural	Yes
Metal	No
Nonmetal	No
Metalloid	Yes
Type	Metalloid
Atomic Radius	114 pm
Electronegativity	2.18 (Pauling scale)
First Ionization Energy	9.815 eV
Density	5.73 g/cm³
Melting Point	817 °C (sublimes at ~615 °C under standard pressure)
Boiling Point	613 °C (at sublimation conditions)
Number of Isotopes	1 stable (Arsenic-75)
Discoverer	Known since ancient times
Year	Unknown
Specific Heat	0.329 J/g·K
Number of Shells	4
Number of Valence Electrons	5