Alkali Earth Metal of the week

Calcium- Ca

   Atomic #-20
   Group:2
   Period:4

  Silvery, soft metal, tarnishes to grayish white
after exposure to ait. Levels in the human are:

   Blood/mg dm-3: 60.5
   Bone/p.p.m: 170000
   Liver/p.p.m: 100-360
   Muscle/p.p.m: 140-700
   Daily Dietary Intake: 600-1400mg
   Total mass in Avg.70kg human: 1kg
  
  Comes from the earth (3.5%), seawater, and the sun.
None in the atmosphere. Calcium is an essential
component in shells, bones,teeth, and plant
structures.