It is given by the ratio of the pressure on a body to the fractional decrease in volume. A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site. Copyright of and ownership in the Images reside with Murray Robertson. The RSC has been granted the sole and exclusive right and licence to produce, publish and further license the Images.
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Jump to main content. Periodic Table. Glossary Allotropes Some elements exist in several different structural forms, called allotropes. Glossary Group A vertical column in the periodic table.
Fact box. Group 14 Melting point Glossary Image explanation Murray Robertson is the artist behind the images which make up Visual Elements. Appearance The description of the element in its natural form.
Biological role The role of the element in humans, animals and plants. Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially. Uses and properties. Image explanation. Lead has been known to, and used by, humans for many centuries. This long history is reflected in the image by the use of an early alchemical symbol for lead and carved Ancient Roman characters. A dull, silvery-grey metal. It is soft and easily worked into sheets.
This easily worked and corrosion-resistant metal has been used for pipes, pewter and paint since Roman times. It has also been used in lead glazes for pottery and, in this century, insecticides, hair dyes and as an anti-knocking additive for petrol. All these uses have now been banned, replaced or discouraged as lead is known to be detrimental to health, particularly that of children.
Lead is still 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. It is often used to store corrosive liquids. It is also sometimes used in architecture, for roofing and in stained glass windows.
Biological role. Lead has no known biological role. It can accumulate in the body and cause serious health problems. It is toxic, teratogenic disturbs the development of an embryo or foetus and carcinogenic.
Daily intake of lead from all sources is about 0. The average human body stores about milligrams of lead in the bones. Natural abundance. Lead is chiefly obtained from the mineral galena by a roasting process. Help text not available for this section currently. Elements and Periodic Table History. Lead has been mined for more than 6, years, and the metal and its compounds have been used throughout history.
Small lead nuggets have been found in pre-Columbian Peru, Yucatan, and Guatemala. The Greeks mined lead on a large scale from onwards and not only knew how to obtain the metal but how to covert this to white lead. Because of its superb covering power, this was the basis of paints for more than years, until the middle of the last century. The Romans employed lead on a large scale, mining it mainly in Spain and Britain, and using it also for water pipes, coffins, pewter tableware, and to debase their silver coinage.
While its mining declined in the Dark Ages it reappeared in Medieval times and found new uses, such as pottery glazes, bullets, and printing type. In the last century it was a fuel additive. Atomic data. Glossary Common oxidation states The oxidation state of an atom is a measure of the degree of oxidation of an atom.
Oxidation states and isotopes. Glossary Data for this section been provided by the British Geological Survey. Relative supply risk An integrated supply risk index from 1 very low risk to 10 very high risk.
Recycling rate The percentage of a commodity which is recycled. Substitutability The availability of suitable substitutes for a given commodity. Reserve distribution The percentage of the world reserves located in the country with the largest reserves. Political stability of top producer A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators.
Political stability of top reserve holder A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators. Supply risk. Relative supply risk 6. Young's modulus A measure of the stiffness of a substance.
Shear modulus A measure of how difficult it is to deform a material. Bulk modulus A measure of how difficult it is to compress a substance. Vapour pressure A measure of the propensity of a substance to evaporate. Pressure and temperature data — advanced. Listen to Lead Podcast Transcript :.
You're listening to Chemistry in its element brought to you by Chemistry World , the magazine of the Royal Society of Chemistry. Hello, this week we're sinking to new depths as we meet the metal that spawned the plumb line, a rock group, plumbing and even poisoning, not to mention a generation of alchemists who tried in vain to turn this substance into gold.
It is of course lead, and here to swing it for us is science writer Phil Ball. Lead is the Eeyore of metals - slow, dull and heavy. Group in Periodic Table. Period in Periodic Table. Block in Periodic Table. Electronic Configuration. Melting Point. Boiling Point. CAS Number.
Abundance in Universe. Abundance in Sun. Abundance in Meteorites. Abundance in Earth's Crust. Abundance in Oceans. Abundance in Humans. Space Group Name. Space Group Number.
Crystal Structure. Electron Configuration. Valence Electrons. Oxidation State. Atomic Radius. Covalent Radius. Van der Waals Radius. Neutron Cross Section.
Young Modulus. Shear Modulus. Bulk Modulus. Poisson Ratio. Mohs Hardness. Vickers Hardness. Brinell Hardness. Electrical Conductivity. In the universe, protons are abundant, making up about half of all visible matter.
The proton has a mean square radius of about 0. The protons exist in the nuclei of typical atoms, along with their neutral counterparts, the neutrons. Neutrons and protons, commonly called nucleons , are bound together in the atomic nucleus, where they account for Research in high-energy particle physics in the 20th century revealed that neither the neutron nor the proton is not the smallest building block of matter.
A neutron is one of the subatomic particles that make up matter. In the universe, neutrons are abundant, making up more than half of all visible matter. It has no electric charge and a rest mass equal to 1.
The neutron has a mean square radius of about 0. Atomic nuclei consist of protons and neutrons, which attract each other through the nuclear force , while protons repel each other via the electric force due to their positive charge.
These two forces compete, leading to various stability of nuclei. There are only certain combinations of neutrons and protons, which forms stable nuclei. Neutrons stabilize the nucleus , because they attract each other and protons , which helps offset the electrical repulsion between protons.
As a result, as the number of protons increases, an increasing ratio of neutrons to protons is needed to form a stable nucleus. If there are too many or too few neutrons for a given number of protons, the resulting nucleus is not stable and it undergoes radioactive decay.
Unstable isotopes decay through various radioactive decay pathways, most commonly alpha decay, beta decay, or electron capture. Many other rare types of decay, such as spontaneous fission or neutron emission are known. It should be noted that all of these decay pathways may be accompanied by the subsequent emission of gamma radiation.
Pure alpha or beta decays are very rare. The periodic table is a tabular display of the chemical elements organized on the basis of their atomic numbers, electron configurations, and chemical properties. The electron configuration is the distribution of electrons of an atom or molecule or other physical structure in atomic or molecular orbitals. Knowledge of the electron configuration of different atoms is useful in understanding the structure of the periodic table of elements.
Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms.
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