By: Melissa M, Mackenna P, Landon B, Zachary K! Block: 7
The metalloids include Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), and Polonium (Po).
Metalloids are the elements found along the stair-step line that separates metals from nonmetals. This line is drawn from between Boron and Aluminum to the border between Polonium and Astatine.The only exception to this is Aluminum which is classified under "Other Metals”. Metalloids have properties of both metals and non-metals.
Boron: Was not officially discovered until 1808 by Sir Humphry Davy, Joseph-Louis Gay-Lussac and Louis Jaques Thenard.
Silicon: Silicon was looked at for the first time by Jons Berzelius in 1823
Germanium: This element was predicted by Clemens Winkler in 1886
Arsenic: The dicoverer of this element is unknown and the date of discovery was known to the anicents.
Polonium: Polouium was the first element discovered by Marie and Pierre Curie in 1898
Tellurium: Tellurium was founded by Franz Muller Von Reichenstein 1782.
Number of Valence Electrons: Every Metalloid has valence eletrons. However, Boron is the only metalloid that has 3 valence electron. Silicon and Germanium have 4 electrons. Also Arsenic and Antimony both have 5 valence electrons. Last but not least the last two Metalloids Tellurium and Polonium have 6 valence electrons.
Boiling and Melting Points of Metalloids:
Boron- Melting Point- 2300C Boiling Point- 2550C
Silicon- Melting Point- 1410C Boiling Point- 2355C
Germanium- Melting Point- 937C Boiling Point- 2830C
Arsenic- Melting Point- 81C Boiling Point- 613C
Antimony- Melting Point- 630C Boiling Point- 1750C
Tellurium- Melting Point- 449C Boiling Point- 990C
Polonium- Melting Point- 254C Boiling Point- 962C
Health and Evironmental Concerns:
Boron has an environmental concerns, when animals are exposed to boron during pregnancy their offspring may suffer from birth defects or delayed development.
Silicon is an health concern considering with lung cancer.
Arsenic causes skin cancer, liver cancer, and lymphatic cancer.
Everyday examples that have metalloids in them !
Silicon: Computer microchips
Germanium: Wide angle camera lenses
Antimony: Batteries, Mascara, pottery
Tellurium: Glass and ceramics
Polonium: A brush that has dust practicals with Polonium in it, that helps clean cameras that are used a lot (for examples movie producers use them to help clean the camera for a good view during the movie)