The poor metals are a group of metals on the periodic table, found in columns 13-15. Three of these metals are toxic, they are Aluminum, Thallium, and Lead. The melting and boiling points are generally lower than transition metals but their electronegativity is higher, and they are softer than all the other metals. They are generally distinguished from metalloids. Occasionally germanium, antimony, and polonium are also included even though they are considered to be metalloids. Poor metals follow the completion of each d-shell.
The 7 poor metals on the periodic table include Aluminum, Gallium, Indium, Tin, Thallium, Lead, and Bismuth. They are found from columns 13-15. They have lower melting and boiling points than transition metals and they are softer and have a higher electronegativity. They have higher boiling points from the same metalloids in the same row. Poor metals are poor conductors for heat and electricity.
Three of these metals are toxic these are Aluminum, Thallium, and Lead. Aluminum is a toxic mineral because it is believed that it is linked to degenerative brain diseases such as Alzheimer’s and Parkinson’s. Thallium is considered a toxic mineral because it can cause hair loss, and stomach aches which leads to vomiting. Lead is considered a toxic mineral because it can damage the nervous system and brain.
Aluminum was first discovered in 1825 and is in group 13 on the periodic table and its atomic number is 13. It's melting point is 660.323°C and its boiling point is 2519°C, its density is 2.70 and its relative atomic mass is 26.982. Aluminum is a silvery-white, lightweight metal and it is soft and malleable. Aluminum is a very lightweight metal that is used for airplane parts and ground aluminum foil. It has a high thermal conductivity, has excellent corrosion resistance and can be easily cast, machined and formed. Aluminum is used in household product, transportation, and for coating.
Thallium was first discovered in 1861 and is in group 13 on the periodic table and it's atomic number is 81. It's melting point is 304°C and its boiling point is 1473°C, its density is 11.8 and its relative atomic mass is 204.38. Thallium is a soft, silvery-white metal that tarnishes easily. The use of thallium is limited as it is a toxic element. Thallium sulfate was used as a rodent killer but is prohibited in most developed countries. Thallium isn't used for much else because of its high toxicity.
Indium was discovered in 1863 and is in group 13 on the periodic table and the atomic number is 49. It's melting point is 156.60°C its boiling point is 2027°C it's density is 7.31, its relative atomic mass is 114.818. Indium is a soft, silvery metal that is stable in air and water. Most indium is used to make indium tin oxide which is an important part of touch screens, flat screen TVs and solar panels. This is because it conducts electricity, bonds strongly to glass, and is transparent. Indium is one the least abundant minerals on earth.
Tin was discovered approximately around 2100BC and is in group 14 on the periodic table and the atomic number is 50. It's melting point is 231.928°C and it's boiling point is 2586°C it's density is 7.287, its relative atomic mass is 118.710. Tin is a soft, pliable metal. Below 13°C it slowly changes to a powder form. Tin is used to coat other metals to prevent corrosion, such as in tin cans, which are made of tin-coated steel. The alloys of tin are important, such as soft solder, pewter, bronze and phosphor bronze. A niobium-tin alloy is used for superconducting magnets. Tin is also deadly to some marine life and it's use has been banned in most countries.
Gallium was discovered in 1875 and is in group 13 on the periodic table and the atomic number is 31. It's melting point is 29.7646°C it's boiling point is 2229°C it's density is 5.91, it's relative atomic mass is 69.723. Gallium is a soft, silvery-white metal, similar to aluminum. Gallium is used to ready alloys with most metals. It is particularly used in low-melting alloys. It is also used as a semiconductor. It has particular properties that make it very versatile. It has important uses in Blu-ray technology, mobile phones, blue and green LEDs and pressure sensors for touch switches. It has a high boiling point, which makes it ideal for recording temperatures that would vaporize a [thermometer].
Bismuth was founded approximately in 1500 and is in row 15 on the periodic table and the atomic number is 83. The melting point is 271.406°C and it's boiling point is 1564°C it's density is 9.79, it's relative atomic mass is 208.980. Bismuth is a high-density, silvery, pink-tinged metal. Bismuth is used by having it mixed with other metals to make it useful. Its alloys with tin or cadmium have low melting points and are used in fire detectors and extinguishers, electric fuses and solders.
Lead was founded during ancient times and it was the first poor metal ever discovered it is in group 14 on the periodic table the atomic number is 82. It's melting point is 327.462° and it's boiling point is 1749°C it's density is 11.3, and it's relative atomic mass is 207.2. Lead is a dull, silvery-grey metal. It is soft and easily worked into sheets. It's used widely used for car batteries, pigments, ammunition, cable sheathing, weights for lifting, weight belts for diving, lead crystal glass, [radiation] protection and in some solders, and it is also used for corrosive liquids.
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