Arsenic (As)
Arsenic (As, element 33) is a metalloid in group 15, period 4. Atomic mass 74.922, electron configuration [Ar] 3d¹⁰ 4s² 4p³, uses and facts.
About Arsenic
Arsenic is a metalloid with the symbol As and atomic number 33. It is a solid at room temperature, and it sits in group 15, period 4 of the periodic table. Arsenic has been known since antiquity.
Arsenic key facts
- Atomic number: 33
- Symbol: As
- Atomic mass: 74.922 u
- Category: metalloid
- Group: 15
- Period: 4
- State at room temperature: solid
- Electron configuration: [Ar] 3d¹⁰ 4s² 4p³
- Electronegativity (Pauling): 2.18
- Melting point: 1090 K (816.85 °C)
- Boiling point: 887 K (613.85 °C)
- Density: 5.727 g/cm³
- Common oxidation states: −3, 0, +2, +3, +5
Electron configuration
The electron configuration of arsenic is [Ar] 3d¹⁰ 4s² 4p³. The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells. Arsenic has 5 valence electrons.
Uses of arsenic
- Semiconductors
- Wood preservative
- Pesticides (historical)
Did you know?
Arsenic was the 'inheritance powder', a favorite poison of medieval Europe due to its tasteless and odorless nature.
Other elements in group 15 and neighbours
Frequently asked questions
What is the atomic number of arsenic?
The atomic number of arsenic is 33, which means every arsenic atom has 33 protons.
What is the electron configuration of arsenic?
The electron configuration of arsenic is [Ar] 3d¹⁰ 4s² 4p³.
What group and period is arsenic in?
Arsenic is a metalloid in group 15, period 4.
What state is arsenic at room temperature?
Arsenic is a solid at room temperature.
What is arsenic used for?
Arsenic is used for semiconductors, wood preservative, pesticides (historical).