Clear Structure of Water Molecule

In nature, we find water as a transparent, tasteless, inorganic, and colorless fluid substance that makes up 3/4th of the global surface area. It also constitutes almost 3/5th of the body weight in adult humans. A single water molecule including positive hydrogen atoms exhibits positive polarity by attracting one another. Water can retain heat for a long time owing to its high specific heat capacity. Water also acts as a universal solvent. Its density is more in liquid form. Large water bodies tend to appear blue as they absorb and reflect sun rays at red wavelengths.

Electron Dot Structure of Water Molecule

A single water molecule has two atomic hydrogens that are bound to one oxygen atom through chemical bonding. The nucleus of each hydrogen atom contains one proton. Almost double the mass of a normal hydrogen atom – deuterium (2H) which has both one neutron and proton in its nucleus, is present in negligible quantities in a water molecule. In nuclear reactors, application of heavy water containing deuterium oxide is observed as a neutron moderator. 

The correct electron dot structure of a water molecule is depicted by a lone oxygen atom showcasing 6 electrons in its valence shell. It is a stable form as the maximum capacity of outer shells must not exceed 8. In the formation of a water molecule when the oxygen atom tends to create a single chemical bond it links one of the valence electrons to the hydrogen nucleus and at the same time receives an electron’s portion from that atom as well. The capacity of the valence shell is fulfilled when the bond is established with two hydrogen atoms. 

:O:

H         H

The correct electron dot structure of a water molecule is shown above. The unshared electrons in the outer shell of the oxygen atom are drawn as dots. 

Instead of dots, the sign ↑↓ can also be used to depict free electron pairs. The electron dot structure of water molecules showing intermolecular hydrogen bonding helps us to point out the feeble hydrogen bonds when compared to ionic bonds between oxygen and hydrogen.

Structure of water molecule in solid form – ice

Instead of two, now there are four hydrogen atoms surrounding each oxygen atom. The loose structure is due to the weak hydrogen bonding of the unshared electron pairs with the distant hydrogen atoms. The other two hydrogen atoms establish covalent bonding to the central oxygen atom. This open structure is not found in liquid as the intermolecular space is less. Thus ice has less density. 

Insights on the Structure of Water Molecule 

Although the structure is simple, still some properties are contrasting when compared to other chemical substances found in nature. For example, we are familiar with a higher density of solid bodies in comparison to fluids. The scenario is the opposite in the case of water as lighter ice floats on the water surface. If ice would have been heavier, then parts of water on earth could not be inhabited by marine animals as the water would entirely freeze in winter. The clear structure of a water molecule also explains its high melting and boiling points. The covalent bond between an oxygen atom and two hydrogen atoms is not linear. The bonding exhibits a typical angle of 104.5 degrees. The electronegativity (δ) of each oxygen atom is higher than the single hydrogen atom. This makes each water molecule polar. This concludes that in addition to intramolecular covalent bonding the hydrogen atoms with high electron affinity simultaneously build weak hydrogen bonds with other molecules of water. This nature describes the high surface tension and viscosity of water. 

Polar nature allows water to form solutions with ionic substances like salts. This solubility is essential for life regulatory reactions. It also helps in cooking where water is used as a medium. Ionic compounds break into constituent cations and anions when they get dissolved in water by the process of hydration. There is no change in their chemical characteristics as the process is a physical change. The hydration number is directly proportional to the charge density because of which anions exhibit lesser hydration numbers due to greater density of hydrogen and anion binding. Non-ionic substances like ethanol also dissolve effectively due to constituent polar O – H bonds that readily interact in an aqueous solution. For the same reason i.e., non-polar structure, fats are water-insoluble. 

Conclusion 

Water readily forms aqueous solutions with polar substances. Though an increase in temperature and pressure promotes solubility of water with non-polar compounds, if the temperature exceeds a certain point then the gaseous state showcases separate properties. It can be used as a combustion medium for toxic wastes. Due to less molar mass, water is a highly viscous liquid. The surface tension is also high when compared to other similar substances like ammonia. Also, water is an amphoteric agent which can act both as an acid and an alkali in chemical reactions. Millions of molecules bind together to formulate one particle or drop of water.