Page 17 - Herlihy: The Human Body in Health and Illness, 3rd Edition

26 SODIUM

Brief description: sodium is a Group 1
element (or IA in older labelling styles).
Group 1 elements are often referred to as
the "alkali metals". The chemistry of
+
sodium is dominated by the +1 ion Na .

27 CALCIUM

Brief description: calcium as the element is
a grey silvery metal. The metal is rather
hard. Calcium is an essential constituent of
leaves, bones, teeth, and shells. Calcium is
the fifth most abundant element in the
earth's crust and makes up more than 3%
of the crust

28 IRON

Brief description: iron is a relatively
abundant element in the universe. It is
found in the sun and many types of stars in
considerable quantity. Iron nuclei are very
stable. Iron is a vital constituent of plant
and animal life, and is the key component of
haemoglobin.

29 PHOSPHORUS