Other important elements include: Na, K , Mg, Ca, Cl.
Important trace elements: Mn, Fe, Co, Cu, Zn, B, Al, V, Mo, I.
Compare these with the most abundant elements in the Universe:
In the Earth's Crust, the most abundant elements: O, Si, Al, Fe, Ca, Na, K.
Particularly important are the elements: H, C, N, O, which can form multiple (single, double and triple) bonds. Because they are small atoms, they will form very strong and stable molecular bonds.
Is Carbon-based Life the only Possible Life?
The attributes of Carbon have already been discussed. But what about
other kinds of life? Silicon is known to make very strong, long
C-like chains. Could Silicon be a basis for life elsewhere?
Probably not.
1) Silicon can not form double bonds. It can only form SiO.
2) It does not combine with any other element to create a gas.
3) It only weakly dissolves in water.
4) It's bonds in chains are much looser and weaker than those made with
Carbon. Thus silicon chains are susceptible to chemical reactions with O,
NH3, Water, which breaks them apart.
Finally, energy must be in a form accessible to life.
To drive biochemical reactions.
Sunlight (photosynthesis), lightning or other electrical discharge
to create organic molecules and the metabolism of these
molecules, heat from hydrothermal systems (mid-oceanic
ridges and such), and energy through chemical interactions (reducing
or oxidizing species in the crust).