Water is polar because of its shape.
In the article that follows, you’ll learn all about the polarity of water.
Is H2O Polar or Nonpolar? (EXPLAINED)
Water is one of the most important substances on our planet due to its unique polar chemical arrangement.
It is known as a universal solvent because it can dissolve more substances than any other liquid.
Its composition makes it endlessly adaptable, which is crucial to life on Earth, affecting our health, the health of plants, and the health of the earth itself.
The Importance of Polarity
A polar substance is one that has both a positive pole and a negative pole.
This means that one part of the molecule must be positive and the other must be negative.
The more polar a molecule is, the more easily it’ll dissolve in water.
This duality of the positive and negative sides of polar substances happens because of an atom’s electronegativity.
To understand electronegativity, we first need to understand how atoms are charged.
The Charges of Atoms
We have to remember that every atom on the periodic table of elements has positive and negative components.
Each atom contains both protons and electrons; protons are positively charged particles and electrons are negatively charged particles.
Atoms in their natural state contain equal numbers of protons and electrons, which means that the atom is neutrally charged.
But, when an atom loses electrons, it becomes more positively charged and turns into an ion.
In turn, an atom that gains electrons becomes more negatively charged and turns into an anion.
What is Electronegativity?
Electronegativity refers to how strongly an atom attracts another atom’s electrons.
When atoms unite to form a molecule, they share their electrons in their outer orbits.
Either an equal sharing of electrons or an unequal sharing of electrons occurs. A nonpolar covalent bond is when two atoms share electrons equally; this is the most stable kind of bond.
In a polar covalent bond, one of the atoms has higher electronegativity than the other, meaning it gets more electrons than the other atom.
This makes the atom with higher electronegativity become negative and the atom with lower electronegativity become positive.
Therefore, the molecule formed with the negative and positive poles is polar.
Contrarily, a molecule without positive and negative poles is nonpolar. In order to find a general idea of an atom’s electronegativity from looking at the periodic table of elements, remember that electronegativity increases from bottom to top and left to right.
So, the most electronegative atom is francium on the bottom left, while helium on the top right is the least electronegative.
The Polarity of Water
As you may know, the chemical symbol for water is H2O.
This means that it has two hydrogen atoms and one oxygen atom.
The oxygen atom is negatively charged, and the two hydrogen atoms bonded to it are positive.
These atoms are arranged so that the oxygen atom is in the middle, with the two hydrogen atoms near each other, but not touching, so it looks like the Mickey Mouse ears.
This asymmetrical structure is important for why water is able to dissolve so many substances because it allows unique placements for the positive and negative poles.
It also has very strong hydrogen bonds between the oxygen and hydrogen, which creates what is called cohesion.
This is what makes water as a substance so flexible, but also helps the molecules stick together, creating surface tension.
For instance, if you fill a cup with water, you can see that the water can go a little over the brim without spilling because of the cohesion the hydrogen bonds create.
The cohesion and surface tension is also why other, lighter substances are able to float in water.
Water’s ability to dissolve most ionic and polar substances due to its bond strength is what earns it the nickname of the universal solvent.
Let’s take table salt, for instance.
The chemical composition of salt is NaCl, or sodium chloride. For two molecules to join, we have to remember the rule that opposites attract, just like with the poles of magnets.
The negatively charged chloride atom is attracted to one of water’s positively charged hydrogen atoms.
The sodium atom is positively charged, so it is attracted to water’s negatively charged oxygen atoms.
The bonds that these oppositely charged atoms create are stronger than the bond in NaCl, so the sodium and chloride atoms are pulled apart, which is what makes it dissolve in the water.
The polarity of water is very important in many areas of life.
Because it is able to dissolve so many substances, it has the ability to transfer and distribute useful nutrients and filter out unneeded wastes.
For example, water is of vital importance to plants, not only helping to move nutrients through the plant’s stem and leaves, but also transporting cohesion allows for substances to be pulled up from the soil by the roots.
It breaks down toxic materials into harmless compounds and absorbs gases.
Water is vital to the function of our kidneys in helping to rid the body of unnecessary substances and the water in our blood helps us absorb helpful nutrients.
Makes sense why 60-70% of our body weight is composed of water, right?
Water seems simple enough; it’s clear, tasteless, and plentiful.
But, it is much more wonderful and complex than it seems.
Next time you go to take a sip from a nice, cool glass of water, remember what a powerful and important substance it is.
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