Ionic or covalent is water?

Water is a tasteless, odourless, and colourless inorganic substance. It is present in all three states, i.e. solid, liquid, and gas, and constitutes the majority of the earth’s hydrosphere (71 percent) and the human body (60 percent).

A water molecule has one oxygen atom and two hydrogen atoms. Many people are curious as to whether the water molecule is covalent or ionic.

Therefore, I’ve written this essay to provide you with further information.

Therefore, is water an ionic or covalent compound? Yes, H2O (water) is a covalent compound, as the hydrogen and oxygen atoms share electrons to form polar covalent bonds due to the small difference in electronegativity between hydrogen (2.2) and oxygen (3.44). By sharing electrons, oxygen and hydrogen atoms form a covalent bond, which leads in the production of a covalent molecule.

The next possible inquiry is “Why is water covalent?”

Why is Water (H2O) Covalent?

Oxygen and hydrogen are both non-metals, and it is a well-established fact that non-metals form covalent bonds with one another.

The oxygen atom has six electrons in its valence shell and requires two additional electrons to complete its octet, whereas both hydrogen atoms require only one electron to achieve stability.

After finishing this article, you must also read the section on the Lewis structure of H2O.

In addition, the difference in electronegativity between the two atoms necessary to establish a covalent connection must be less than 1.6. (few books mention it to be less than 2).

In the instance of water, the Oxygen atom’s electronegativity is 3.44 and the Hydrogen atom’s is 2.1, resulting in an electronegativity differential of 1.34 and a covalent link between the two atoms.

In the case of water molecules, however, the covalent link is produced by oxygen and hydrogen atoms sharing electrons unequally.

Since oxygen is more negatively charged than hydrogen, it pulls the shared pair of electrons slightly towards itself, giving the oxygen atom a tiny negative charge and the hydrogen atom a slight positive charge; hence, water is a polar covalent molecule.

The polarity of water molecules will be discussed in the following sections.

What causes atomic bonding?

If you knew the cause for chemical bonding between distinct atoms, you would have a greater grasp of the previously mentioned idea.

Atoms tend to stabilise their valence shell in accordance with the octet rule by completing their octet, or acquiring eight electrons in their outermost shell.

Hydrogen and helium are the only exceptions to the octet rule. Hydrogen, a group one element, contains one electron in its outermost shell and requires two valence electrons to be totally satisfied.

Hydrogen’s stability derives from the electrical configuration of helium, the nearest noble gas, which is stable with two valence electrons.

Atoms may lose, gain, or share their valence electrons in order to complete their octet, which causes them to form ionic or covalent connections. This maximises an atom’s stability.

What are the differences between Ionic and Covalent Compounds?

As their name suggests, ionic compounds are created through ionic bonding.

These are the electrostatic forces between the two ions with opposite charges, anion (positive) and cation (negative) (negative).

Depending on the number of atoms involved, the ions may be monoatomic, such as Na+, K+, and Cl-, or polyatomic, such as HSO4- and NH4+. The majority of ionic bonds are produced between metals and non-metals.

The difference in electronegativity between the combining atoms is the primary cause of ionic bond formation.

When the difference in electronegativity is greater than 1.6, ionic bonds are formed.

At the time of chemical bond formation, the more electronegative atom attracts the electron pair to itself, so acquiring a negative charge, while the atom donating the electron gains a positive charge.

Typically, the net charge on such compounds is zero because the positive and negative charges cancel each other out, making them electrically neutral.

CaF2 is an intriguing ionic chemical. Read the article on whether CaF2 is ionic or covalent.

The covalent bond, on the other hand, is created when the valence electrons of two bonding atoms are shared.

Typically, these bonds exist between non-metallic atoms with comparable electronegativity (less than 1.6).

Covalent substances are electrically neutral and weak conductors of electricity because they lack ions.

Unlike ionic compounds, they often exist as gases or liquids at normal temperature and have low melting and boiling points.

Polar covalent bonds can be distinguished from non-polar covalent bonds.

Polar Covalent Bond versus Non-Polar Covalent Bond

In non-polar covalent bonds, the electrons are shared evenly between the two atoms, i.e., they spend equal time around each nucleus and the chance of these electrons being close to each atom is equal.

These bonds exist between atoms that are identical, such as H2, Cl2, etc. Here, the difference in electronegativity is less than 0.40.

Consult the article regarding the polarity of H2.

When a covalent bond is formed between dissimilar atoms, however, the shared electrons are not equally distributed between the two atoms, resulting in a slight positive and slight negative charge on the atom from which electrons are pulled away and the atom that pulls electrons towards itself, respectively.

This is owing to the difference in electronegativity between the two atoms, which should fall between 0.4 and 1.6.

Similar to H2O, the oxygen atom is more electronegative, which increases the likelihood of finding a shared pair of electrons near the oxygen atom. As a result, oxygen acquires a tiny negative charge while hydrogen acquires a slight positive charge.

These partial charges are denoted by the Greek character delta and transcribed as + and -.

Polarity of the Water (H2O) Molecule

As previously discussed, the covalent link between hydrogen and oxygen atoms within a water molecule is polar.

Polarity of H2O is a result of its curved shape, which results from the attraction and repulsion forces between the two atoms.

The more electronegative oxygen atom attracts electrons to itself, resulting in a negative charge around this atom and a tiny positive charge on the hydrogen atoms.

Due to their identical charges, the two positively charged hydrogen atoms are equally attracted to the negatively charged oxygen atom yet remain as far apart as possible.

In addition, the lone pair of electrons present on the oxygen atom tend to resist each other, driving hydrogen atoms away from it.

This results in a deformation of linear geometry and the formation of an angle of 104.3°.

In addition, I have written a specific article on this subject. Check out the polarity of water.

Electronegativity

Electronegativity is the tendency of an atom to draw electrons toward itself.

It plays a crucial function in chemical bonding and is dependent on the difference in electronegativity between the two atoms.

It is possible to establish whether the bond between them is covalent or ionic. Pauling’s scale is used to measure the electronegativity of any substance. This can be inferred from the following table:

Difference in bond type electronegativity

Pure/Non-polar covalent < 0.4

Polar covalent Between 0.4 – 1.6

(occasionally 2.0)

Ionic >1.6 (sometimes 2.0)

Electronegativity increases towards the top of a column and declines from right to left across a row in the periodic table.

Qualities of water

Water is amphoteric, meaning it can function both as an acid (proton donor) and a base (proton acceptor). It has a pH of 7, indicating that it is a neutral chemical.

It is known as a universal solvent since it can dissolve the most compounds compared to any other solvent.

The table below outlines a number of water’s essential properties:

Properties Value

Molar Mass 18.015 gm/mol

Point de fusion 0° C

Boiling Point 100 ° C

At room temperature, the density is 0.99701 g/cm3.

71.9 dyne/cm3 (at room temperature) is the surface tension.

Vapour Pressure (at room temperature) 23.75 torr

Dipole Moment 1.85 D

Hydrogen Bond

These are the intermolecular forces that occur between an electronegative atom and a hydrogen atom due to their dipole-dipole interaction.

Due to hydrogen bonding, the hydrogen atoms of one water molecule are connected to the oxygen atom of another water molecule.

These forces are relatively weak compared to true chemical bonds, such as ionic or covalent bonds, but strong compared to dispersion forces and dipole-dipole interaction.

These play a crucial part in determining the different properties of water, such as its form, solubility, etc. Due to hydrogen bonding, the melting and boiling points of water are high.

Utilizations of Water

Water comprises over 60 percent of our body mass and is essential to our bodily functioning.

Within the human body, it is necessary to

• Facilitate temperature regulation via perspiration

• To support the digestive process

• To perform cognitive operations (dehydration can adversely affect the brain functioning)

• For elimination (through perspiration, urination, etc.)

• Aids in boosting metabolism, hence enhancing a person’s physical strength.

In addition to the human body, water is an essential component of the environment for the survival of the vast majority of living species.

Humans require it for agriculture, many industries, recreational activities, and so on.

Conclusion

The oxygen and hydrogen atoms in water are somewhat negatively and positively charged, respectively.

Due of the slight difference in electronegativity between hydrogen and oxygen atoms, water is covalent.

Water’s polarity is a result of its bent shape, which is caused by numerous intramolecular forces.

In addition to covalent bonding, hydrogen bonding is another sort of chemical interaction that happens between water molecules.

Read more: Structure of O2 Lewis, Molecular Geometry, and Hybridization

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.

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