Periodic Table -> Lead
Lead DetailsLead Symbol:
PbLead Atomic Number:
82Lead Atomic Weight:
207.19What is Lead?
is a chemical element in the carbon group under number 82. Its symbol is Pb, after the Latin plumbum. As we know, in the past, all the plumbing was made of lead, which results in poisoning and death. Thankfully, it no longer is.
Lead is soft and considered a poor metal, which means that it is a metallic element in the p-block. It is not clear why these elements are considered poor metals. What sets them apart from the others is that their electro-negativity is higher while their melting and boiling points are lower than that of transition metals. The other poor metals are tin, gallium, aluminum, bismuth, indium, and thallium. Lead is also considered a heavy metal. Its exposure to air renders it gray in color; otherwise it is whitish and silvery when melted. Some consider lead to be the most stable element of all because of its high atomic number.
Lead has three stable isotopes and one unstable isotope. All of them are natural. The first isotope, Pb-204, is slightly radioactive and is considered primordial, meaning that it is older than the Earth itself. This is the unstable one. The stable isotopes – Pb-206, 207 and 208 – are generated from isotopes of the elements thorium and uranium.
Lead is, as mentioned, a metal that has been used since the beginning of time. It is easy to use and extract, being ductile and malleable. It has been used as early as 6400 BC, as evidenced by lead beads found in what is Turkey today. Lead was used with arsenic in the Bronze Age.
Lead has many uses to this day, notwithstanding the fact that water pipes are not made of it anymore. It is used in construction, shots, bullets, batteries, and as a shield from radiation. Other uses include in some alloys and in solders. It is useful in dating because its half-life is extremely high.
One major use of lead is in the glass of television and computer screens, shielding the viewer from radiation. Other uses are in lead crystal glassware, as weight in sports equipment, in solders, cables, ammunitions, and sheeting.
Lead is soft, dense, and malleable. It is very resistant to corrosion, which is why it is frequently used in construction. Adding small amounts of calcium and antimony serves to harden lead.
The element does not occur in nature frequently. It is found in zinc, silver and copper ore. Galena is the major mineral containing lead – around 87 percent, more specifically. It is also found in anglesite and cerussite.
Lead has disastrous side effects in high levels. It inflicts heavy damage to the central nervous system and causes blood and brain disorders. It accumulates in the bones and in soft tissues. Other unwanted effects include diminished learning abilities, declined fertility in men, and behavioral disruptions in children, including hyperactivity, impulsive behavior, and aggression. Lead poisoning has been documented in antiquity and still occurs to this day. In fact, this element is 1 out of 4 metals, which have the most serious effects on human health. The element can enter the body through air (15 percent), water (20 percent), and the food (65 percent). Cigarette smoke contains small amounts while foods such as wine, soft drinks, grains, seafood, meats, and vegetables and fruit may contain significant amounts.
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