The Periodic Table in Minutes by Dan Green

Author:Dan Green
Language: eng
Format: epub, mobi
Tags: SCI000000 SCIENCE / General
Publisher: Quercus

Calcium

A soft, shiny and reactive metal, silver-grey calcium is rarely encountered in its pure form. Instead, this reactive element is a great builder, readily forming ionic salts. Element 20 is the fifth most common in the Earth’s crust, where it is mostly found as calcium carbonate in limestone and chalk rocks. We carry more than a kilogram (2.2 lb) of it around as calcium phosphate in our bones, while quicklime, created by heating calcium carbonate, is the key ingredient in the 5.2 billion tonnes of concrete cement produced each year.

Calcium compounds dissolve easily in water, especially when it is slightly acidic. Although limestone is a hard-wearing rock, it is not weatherproof and is eaten away by rain and groundwater. The calcium cations released into the water make it ‘hard’ – prone to leaving limescale deposits and resistant to making suds with soap. Sea creatures build their shells out of dissolved calcium carbonate, extracted from the water. These tough structures persist long after the animal dies, and can become fossils.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.