Shape of Ammonia Molecule

The ammonia molecule features a trigonal pyramidal shape as predicted through the valence shell electron set repulsion theory with an experimentally determined bond angle of 106.7°. The main nitrogen atom provides five outer electrons with one more electron from every hydrogen atom.

This gives an overall of eight electrons or four electron sets that are set up tetrahedrally. Three of these electron sets are used like bond pairs, which leaves one lone set of electrons. The lone set of electrons repel more highly than bond pairs, therefore the bond angle is not 109.5°, as expected for a normal tetrahedral arrangement, however is measured at 106.7°.

The nitrogen atom within the molecule features a lone electron set, which makes ammonia a base, a proton acceptor. This shape provides the molecule a dipole moment and makes it polar. The molecule's polarity and, especially, its capability to form hydrogen bonds, makes ammonia extremely miscible with water.

Ammonia is moderately basic, a 1.0 M aqueous solution features a pH of 11.6 and if a solid acid is put into such a solution until the solution is neutral (pH = 7), 99.4% of the ammonia molecules are protonated.

Characteristics of Ammonia

Ammonia is a substance having the formula NH3. It is generally came across like a gas with a characteristic pungent odor. Ammonia contributes significantly to the nutritional requirements of terrestrial organisms by serving like a precursor to food products and fertilizers. Ammonia, either indirectly or directly, is also a foundation for the synthesis of numerous pharmaceuticals. Although in broad use, ammonia is both hazardous and caustic.

Ammonia, as employed commercially, is often referred to as anhydrous ammonia. This word emphasizes the lack of water in the material. Because NH3 boils at -33 °C, the liquid should be stored at low temperature or under high pressure. Its heat of vaporization is, however, sufficiently excellent that NH3 can be quickly handled in ordinary beakers in a fume hood.

Additional characteristics of ammonia are as follows:

Pungent Smell

Colourless Gas

Can be easily liquified due to strong Hydrogen Bonding between molecules

Lighter than Air (its density being 0.589 times that of air)

One of the most characteristic properties of ammonia is its basicity.

Liquid ammonia possesses strong ionizing powers

It is a protic substance, and is capable of formation of "amides"

it can also act as an extremely weak acid.

Ammonia Molecule Structure

The ammonia molecule is actually a polar covalent molecule composed of 3 atoms of Hydrogen and one atom of Nitrogen. The single Nitrogen atom in an ammonia molecule is bonded to 3 atoms of Hydrogen via the sharing of 3 electron pairs, one with each atom of Hydrogen. In each of these 3 covalent bonds created between Hydrogen and Nitrogen, one electron is provided by the Hydrogen and one electron is provided by Nitrogen atom. This forms one set of shared electrons. The structure of an ammonia molecule is listed below.

A single nitrogen atom has five electrons in its valence shell in the normal situation (that is, when it has not misplaced any electrons).

The ammonia molecule is created by covalent bonding among three Hydrogen atoms and one Nitrogen atom.

One of each valence electron of nitrogen and one electron of hydrogen mix and form a single covalent bond. Likewise three bonds are created between the Nitrogen atom and three Hydrogen atoms respectively.

Each Hydrogen atom provides 1 valence electron.

Since 3 of the 5 valence electrons of nitrogen are shared, the two electrons that stay unshared are called a lone pair of electrons.

Thus you can find a total of 8 valence electrons in the ammonia molecule, 5 from nitrogen and 3 from hydrogen.

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