Water is the most abundant compound on Earth's surface, covering about 70 percent of the planet.
In nature, water
exists in liquid, solid, and gaseous states.
Many substances dissolve in water and it is commonly referred to as the universal solvent.
Water is the chemical substance
with chemical formula
H2O
The water molecule, as a whole, has 10 protons and 10 electrons, so it is neutral.
In a water molecule, the oxygen atom and hydrogen atoms share electrons in covalent bonds, but the sharing is not equal.
In
the covalent bond between oxygen and hydrogen, the oxygen atom attracts
electrons a bit more strongly than the hydrogen atoms.
The
unequal sharing of electrons gives the water molecule a slight negative
charge near its oxygen atom and a slight positive charge near its
hydrogen atoms.
When a neutral molecule has a positive area at one end and a negative area at the other, it is a polar molecule.
Water
molecules attract one another based on the attraction between the
positive end of one water molecule and the negative end of another.
