Period 8 Lindsey Ipson, Mike Napoli, Emma Fox Boron (#5) • • • • • • • • • • • • Element Symbol: B Electron configuration: 1s2 2s2 2p1 Boron is a solid at room temperature Is a metalloid Hard texture Poor conductor Melting Point: 2349 K (2076°C, 3769°F) It is inert Never found free in nature Used as a lubricant ***Did you know?*** Boron nitrate, a boron compound, can be used to make materials that are almost as hard as diamonds! Aluminum (#13) • • • • • • • • • • • • Element Symbol: Al Electron Configuration: 1s2 2s2 2p6 3s2 3p1 Solid at room temperature Is a metal Hard but malleable, lightweight but strong Melting Point: 933.47 K, (660.32 °C, 1220.58 ° F) Good conductor of heat and electricity Aluminum is extremely reactive, even under normal conditions Occasionally found in its free state in nature, but mostly as a compound Uses: kitchenware, aluminum foil, airplanes, boats ***Did you know?*** There is more aluminum in the Earth’s crust than any other metal. Gallium (#31) • Element Symbol: Ga • Electron Configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1 • Solid at room temperature • Is a metal • Brittle • Not found in nature in its free state • Melting point 302.9146 K (29.7646°C, 85.5763°F) • Decent conductor (not the best or worst) • Somewhat reactive with alkali metals and acids • Uses: Effulgent mirrors, some thermometers • ***Did you know?*** Gallium will melt if held in the human hand. Indium (#49) • • • • • • Element Symbol: In 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p1 Solid at room temperature Metal Very soft, one of the softest known metals Rarely found in nature in its free state, found mostly in compounds • Melting Point: 156.6° Celsius • Conducts heat • Not radioactive • Inert • Uses: engine lubricant, video/laptop/computer/television screens • ***Did you know???*** Indium produces a “screaming” sound when it is bent, and it writes like a pencil. Also, it is softer than lead. Thallium (#81) Element Symbol: Tl Electron configuration: [Xe] 6s2 4f14 5d10 6p1 Solid at room temperature Soft-can be cut with knife Melting Point: 304° C Good conductor at room temperature Only found in compound form, not found free naturally • Uses: Treats infections and ringworms, makes some glasses, ant/rodent poison • Highly reactive, erodes in contact with air • ***Did you know?*** Thallium was discovered by Sir William Crookes, and it is very poisonous and suspected of being used in some murder cases. • • • • • • • Conclusion The Boron group consists of mostly metals, with one metalloid. They are not usually found in nature in their free states. Their most common uses are for machines and appliances.