Answer:
At is a metalloid
Explanation: Meaning that it displays some of the characteristics of a metal but can also display characteristics of nonmetals. Silicon is one such element. Elemental Silicon has a dark lustrous metallic appearance but it is quite brittle. Some authorities include Astatine as a halogen as it has seven electrons in its valence shell placing it just below iodine in period 17 VIIA. Additionally, because Astatine is only ever found naturally as the result of radioactive decay from more dense elements it is the rarest naturally occurring element in Earth's crust.
I hope this helps at least a little.
Regards,
JR Holt
Chemist retired