The group 14 elements  (Page 2/3)

Tin

Tin is one of the earliest metals known. When the addition of about 5% tim to molten copper produced an alloy (bronze) that was easier to work and much harder than copper, it revolutionized civilization. The widespread use of bronze to make tools and weapons became part of what archaeologists call the Bronze Age. The Bronze Age arrived in Egypt, Mesopotamia and the Indus Valley culture by around 3000 BC.

Lead

Lead has been commonly used for thousands of years because of its ease of extraction, and its ease of smelting. Lead beads dating back to 6400 BC have been found in Çatalhöyük in modern-day Turkey, while lead was used during the Bronze Age.

Abundance

Carbon and silicon are amongst the most abundant elements ( [link] ). Silicon is the second most abundant element (after oxygen) in the Earth’s crust, making up 28% of the crust. Carbon is the fourth most abundant chemical element in the universe after hydrogen, helium, and oxygen. In combination with oxygen in carbon dioxide, carbon is found in the Earth's atmosphere (in quantities of approximately 810 gigatonnes) and dissolved in all water bodies (approximately 36,000 gigatons). Around 1,900 gigatons are present in the biosphere. Hydrocarbons (such as coal, petroleum, and natural gas) contain carbon amounts to around 900 gigatons. Natural diamonds occur in the rock kimberlite, found in ancient volcanic "necks," or "pipes". Most diamond deposits are in Africa but there are also deposits in Canada, the Russian Arctic, Brazil, and Australia.

Isotopes

[link] summarizes the naturally occurring isotopes of the Group 14 elements.

Although radioactive, carbon-14 is formed in upper layers of the troposphere and the stratosphere, at altitudes of 9–15 km. Thermal neutrons produced by cosmic rays collide with the nuclei of nitrogen-14, forming carbon-14 and a proton. Because of its relatively short half-life of 5730 years, carbon-14 is absent in ancient rocks, but is incorporated in living organisms.