Arsemic has 33 ground state electrons and these are arranged in the following configuration: [Ar].3d10.4s2.4p3. Which can be seen in the diagram bellow:
The formation of the element of Arsenic can be achieved by smelting loellingnite (FeAs2) at 675oC in the absence of air and condensing the sublimed element.
Arsenic does not melt when heated, it turns staight into a gas. This is called sublimination. However, at 814 C and very high pressure it can be forced to melt. As an element Arsenic remain stable in the air but if there is moisture in the air then the outer surface will begin to oxidise. It will tarnish to a bronze colour, before being completely covered by a black layer. Arsenic will not though react with water without the presence of air.
Heating Arsenic in the air will produce a blue flame and give off a garlic-like odour. The reaction can be seen below:
Arsenic as an element has three known allotropic forms.