Ca
Calcium · element 20
Alkaline Earth Metal · Solid at room temperature
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.
Key facts
Atomic mass
40.0784 u
how heavy one atom is
Phase (room temp.)
Solid
Density
1.55 g/cm³
how tightly packed it is
Melting point
1115 K (842 °C)
when solid turns to liquid
Boiling point
1757 K (1484 °C)
when liquid turns to gas
Period
4
its row in the periodic table
Group
2
its column in the periodic table
Block
S-block
the neighbourhood it lives in
Electronegativity
1
how strongly it pulls electrons
Electron configuration
[Ar] 4s2
where its electrons live
Shells
2 · 8 · 8 · 2
electrons in each layer, inside to out
Discovered by
Humphry Davy
who found it
Source: Wikipedia