Question

Choose one element you commonly encounter and explain if you encounter it most often in its elemental form or as a compound (and name which compound(s)), discuss its properties, structure, and where it is commonly found. Include any other information you think might be useful or interesting.

YOU MUST INCLUDE ALL REFERNCES IF YOU USED ANY OUTSIDE SOURCES!

answer this question with 100 word or over.

Answer 1

A common element encountered by all living beings in oxygen. Oxygen is encountered both as an element and in its compounds of which water is most common. Oxygen is found in the atmosphere along with nitrogen and other gases. Our earth’s atmosphere is roughly 20 % oxygen. Oxygen is also the third most abundant element in the Milky Way galaxy. Oxygen is a gas at room temperature with boiling point at -183 ^oC. Oxygen is found in as diatomic molecules, O₂. A molecule of oxygen has two oxygen atoms doubly bonded to each other. The bond is non-polar because the two atoms have identical electronegativity values.

A commonly found allotrope of oxygen is ozone, which is the triatomic molecular form of oxygen. Ozone or O₃ is found in the stratosphere and serves to block ultraviolet radiations from reaching the surface of the earth.

Oxygen is essential to all life and it supports photosynthesis in plants and respiration in both plants and animals. A representative equation for photosynthesis is given here:

6 CO₂ + 6 H₂O + Light --------------> C₆H₁₂O₆ + 6 O₂

Oxygen supports a variety of processes that occur everyday. Such as the combustion of fossil fuel and oxidation of metals. A very common example of metal oxidation is the rusting of iron which is represented by the following equation:

4 Fe + 3 O₂ -----------> 2 Fe₂O₃

_{It is interesting to note that oxygen is (by weight) the most abundant element in the earth's crust and is followed by silicon and aluminium.}

_References:

https://en.wikipedia.org/wiki/Oxygen#Occurrence

https://en.wikipedia.org/wiki/Rust#Chemical_reactions

http://www.chemicalelements.com/elements/o.html