Is Ammonia (NH3) ionic or covalent? Types of bond in NH3

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Is ammonia (NH3) ionic or covalent compound? bond types in NH3

Ammonia appears as colorless gas and has a strong pungent odor having chemical formula NH3. It is made up of one nitrogen and three hydrogen atom. It is one of the important sources of nitrogen for plants and animals. Exposing to open air, liquid ammonia will quickly turn into a gas. Ammonia is easily liquified due to strong hydrogen bonding between molecules. 

In this article, we will discuss Is Ammonia (NH3) ionic or covalent? Bond types in ammonia, etc.

So, Is NH3 ionic or covalent? Ammonia (NH3) is a covalent compound because the bond is formed between one nitrogen and three hydrogen atom by the sharing of electrons. Also, the difference of electronegativity between nitrogen and hydrogen atoms on the Pauling scale is not big enough to make an ionic bond in the NH3 compound.

Let’s read in detail, why NH3 is a covalent compound? How covalent bonds formation takes place in NH3?

Name of MoleculeAmmonia
Chemical formulaNH3
Molar mass17.031 g/mol
Bond typeCovalent
NatureWeak base
pH value11

Why Ammonia (NH3) is an covalent compound?

A covalent compound is a chemical compound that is made when two nonmetals or two p-block elements together share their valence electron with each other to complete the octet and attains stability.

The sharing of valence electrons between two atoms makes a bond which is called a covalent bond. “Valence electrons are the outermost shell electron of an atom”.

Ammonia (NH3) is a covalent compound because the nitrogen and hydrogen atoms are nonmetals in nature, they don’t have any tendency of either accepting or donating the electrons but both nitrogen and hydrogen atoms have a tendency to share their valence electron with each other and hence, complete the octet and makes a stable NH3 covalent compound.

Why covalent bond is formed in NH3 (ammonia)

As we see in the above figure when one nitrogen and 3 hydrogens approach each other, they make a covalent bond in NH3 because of sharing of electrons.

Examples of some compounds that form covalent bonds – H2O, H2S, SO2, NO2, AlCl3, etc.

Also Read:

How covalent bond is formed in NH3 (ammonia)?

The covalent bond is formed in NH3 because one nitrogen and 3 hydrogen atom share the valence electron with each other to get stability.

Let’s see how covalent bond formation takes place in NH3.

There are two types of atoms present in the ammonia molecules – hydrogen and nitrogen atom.

⇒ The hydrogen atom is a nonmetal that belongs to Group I in the periodic table and has only one valence electron in the outermost shell.

valence electron of hydrogen in NH3 covalent bonding

⇒ The nitrogen atom is also a nonmetal that belongs to Group 15 in the periodic table and has a 5 valence electron in its outermost shell.

valence electron of nitrogen in NH3 covalent bonding

The rule is when two or more atoms come together then they want to complete their octet i.e. having 8 valence electrons in the outermost shell, to attains stability. The octet can be completed either by sharing the valence electrons or completely transferring the valence electron to another atom.

In the case of an NH3 molecule, when nitrogen and hydrogen atom approaches, they completed their octet by sharing the valence electrons with each other and attains stability.

Note: The hydrogen atom has only one valence electron in its outermost shell and for completing the octet it needs only one more electron.

Hydrogen atom is exception to the octet rule as it need only two valence electron in its outershell to complete the octet.

And the nitrogen atom has 5 valence electrons in its outermost shell and it needs 3 more electrons to complete the octet and attains stability.

Therefore, both hydrogen and nitrogen atoms will share the electrons with each other to completing the octet and due to this, a bond is formed between them which is called a covalent bond.

how covalent bond is formed in NH3 (ammonia)

As we see in the above picture of covalent bond formation in NH3, the nitrogen atom has 5 valence electron in its outermost shell and it needs 3 more to complete the octet, hence, 3 hydrogen atom shares one electron each with the nitrogen atom.

In this process, 3 hydrogen atom and one nitrogen atom completed their octet as the nitrogen atom gets 8 electrons in its outer shell and each hydrogen gets 2 electrons in their octet shell.

So, every atom in the NH3 molecule completed its octet by sharing electrons, hence, makes a covalent bond.

Therefore, we can say ammonia (NH3) has a three covalent bond(N-H) that contains 6 shared pairs of electrons or bonded pairs of electrons.

Note: NH3 molecule also contains 2 lone pairs of electrons but they never take part in the formation of covalent bond, only shared electrons are used to makes a covalent bond. After all, the covalent bond is made between the two atoms that share the electrons with each other.

Why is NH3 not a ionic compound?

The NH3 molecule is not an ionic compound because the difference in electronegativity value between nitrogen and a hydrogen atom is not big enough to make an ionic bond between them according to the Pauling scale.

According to the Pauling scale of electronegativity-

  • The covalent bond is formed between the two atoms when their electronegativity difference occurs less than 1.7.
  • The ionic bond is formed between the two atoms when their electronegativity difference occurs more than 1.7.

pauling scale for chemical bonds

Now check the electronegativity difference in NH3 molecule-

⇒ The electronegativity value for hydrogen atom = 2.2

⇒ The electronegativity value for nitrogen atom = 3.04

∴ The difference of the electronegativity between nitrogen and hydrogen atoms = 0.84

So, the difference in electronegativity in the N-H bond is less than 1.7, hence, it is low enough to make a covalent bond between them as per the Pauling scale of electronegativity.

Also, the main difference in ionic or covalent is that an ionic bond is formed when either donating or accepting the electrons occurs between two atoms, and a covalent bond is formed when only sharing of electrons occurs between two atoms.

Is NH3 covalent or ionic?

The nitrogen and hydrogen atoms in the NH3 molecule can never transfer their electrons because their octet can be completed only when they share the electrons with each other, hence, the bond formed in the NH3 molecule is covalent in nature rather than ionic.

Examples of some ionic compounds – MgO, Na2O, MgCl2, NaCl, etc.

Also Read:

Is ammonia (NH3) pure covalent compound?

A pure covalent bond is mostly formed in the molecule that has the same type of atoms and the same electronegativity, for example – O2, F2, Cl2, etc.

Basically, a homonuclear molecule has the ability to form a pure covalent bond because the electronegativity of atoms is the same, hence, sharing of electrons is also equal in them.

In short, a pure covalent bond is formed between the atoms when they share an equal number of electrons.

So, Is NH3 a pure covalent compound? No, NH3 is a not pure covalent compound because it is a heteronuclear molecule that contains different types of atoms (nitrogen and hydrogen atom), and their electronegativity is also not the same.

The electronegativity for hydrogen is 2.2 whereas, for nitrogen, it is 3.04. So, the electrons are more shared towards the nitrogen atom as it is higher electronegative than the hydrogen atom, hence, unequal sharing of electrons occurs between nitrogen and hydrogen atoms.

So, the bonds formed in the NH3 molecule are not a pure covalent bond, hence, NH3 is not a pure covalent compound.

Is NH3 a pure covalent compound?

Is NH3 polar covalent or nonpolar covalent compound?

A polar covalent compound is formed when the unequal sharing of electrons occurs between two atoms because of their difference in electronegativity value.

When the difference of electronegativity value between two atoms lies in between 0.4 to 1.7, then the bond formed between two atoms is polar in nature according to the Pauling scale of electronegativity.

polar covalent bond

A nonpolar covalent compound is formed when the equal sharing of electrons occurs between two atoms because of the very little difference in their electronegativity value.

When the difference of electronegativity value between two atoms is less than 0.4, then the bond formed between two atoms is nonpolar in nature according to the Pauling scale of electronegativity.

nonpolar covalent bond

So, Is NH3 a polar covalent or nonpolar covalent compound? NH3 is a polar covalent compound because the electronegativity difference between nitrogen and a hydrogen atom is 0.84 which is in the range of the Pauling scale of the polar compound from 0.4 to 1.7.

Also, the unequal sharing of electrons occurs in NH3 molecules because nitrogen(3.04) is higher electronegative than a hydrogen atom(2.2), hence, it will pull more electrons towards itself, hence, the nitrogen atom induced a negative charge on it and hydrogen atoms get a slightly positive charge.

The separation of charges generates the dipole moment directed from positive to negative, hence, due to all these a bond is formed between nitrogen and hydrogen, which is called a polar bond.

Is NH3 (ammonia) polar covalent or nonpolar covalent compound

Properties of ammonia

  • It has a molar mass of 17.031 g/mol.
  • It has a boiling point of −33.34 °C and a melting point of −77.73 °C.
  • Ammonia has a strong pungent odor and appears as a colorless gas.
  • The dipole moment of ammonia is 1.42 D.
  • It has the molecular shape of the trigonal pyramid.
  • It behaves as a weak base.
  • Ammonia is lighter than air and easily liquefied due to the strong hydrogen bonding between molecules.
  • The ammonia molecule readily undergoes nitrogen inversion at room temperature.

Uses of ammonia

  1. Ammonia is considered a building block for the synthesis of many pharmaceutical products.
  2.  It is used as a fertilizer in the agriculture sector.
  3. It is used in the manufacture of plastics, textiles, dyes, and other chemicals.
  4. It is also used as refrigerant gas and for the purification of water supplies.
  5. It is used to alter the pH in the fermentation process.
  6. It is used for the treatment of cotton materials.
  7. Ammonia is used as an antimicrobial agent for food products.
  8. It is used for cleansing purposes on many surfaces.
  9. It is used in the manufacture of synthetic fiber like nylon and rayon.
  10. It is used as a precursor to nitrogenous compounds.

FAQ

Why do atoms in NH3 share the electron with each other to complete the octet and make a covalent bond?

This is because nitrogen and hydrogen are nonmetals in nature, that makes them more prone to sharing the electron with each other, also, the transferring of electrons cannot take place between nitrogen and hydrogen atoms because for competing the octet they need to share the electrons as both atoms have incomplete octet shell.

Why is NH3 not a pure covalent compound?

The nitrogen atom is more electronegative than hydrogen, hence, it attracts more electrons towards itself. So, the unequal sharing of electrons occurs between nitrogen and hydrogen. This makes an NH3 molecule a non-pure covalent bond.

How covalent bond is formed in NH3 (ammonia)?

The hydrogen atom has one valence electron and the nitrogen atom have 5 valence electrons in its outermost shell, hence, hydrogen needs 1 electron, and nitrogen need 3 more electrons to complete the octet, so, each hydrogen atom in the NH3 molecule shares the 1 electron with a nitrogen atom.

Hence, both of these atoms get full octet by sharing the electrons with each other. And in this process, a bond is formed between them which is called a covalent bond.

Summary

  • Is ammonia (NH3) ionic or covalent? NH3 (ammonia) is a covalent compound because the bond is formed between one nitrogen and three hydrogen atoms through the sharing of electrons with each other.
  • Ammonia (NH3) is not a pure covalent compound as electrons are shared more towards nitrogen atoms, hence, unequal sharing occurs in it.
  • The covalent bond formed in the NH3 molecule is polar in nature as nitrogen is more electronegative than hydrogen atom hence, it strongly pulls an electron towards itself and this generates the dipole moment which leads to its polar nature.
  • The difference in electronegativity between nitrogen(3.04) and Hydrogen(2.2) is 3.04–2.2=0.84 which is lower than 1.7, hence, according to the Pauling scale, the bond formed between nitrogen and a hydrogen atom(N-H) is covalent in nature.
  • There are three N-H covalent bonds present in the NH3 molecule.
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