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What is an Ammonia Molecule?
Nitrogen and hydrogen are both non-metals.
A nitrogen atom has 5 electrons in its outer shell.
Nitrogen is in group 5 of the periodic table.
A hydrogen atom has 1 electron in its outer shell.
Hydrogen can only form 1 bond.
Three hydrogen atoms each share their 1
nitrogen to form three covalent bonds
and make an ammonia molecule (NH3).
This is a picture of an ammonia molecule.
By sharing the two electrons where the shells touch
each hydrogen atom can count 2 electrons in its outer shell
and the nitrogen atom can count 8 electrons in its outer shell.
These full outer shells with their shared electrons
are now stable, and the NH3 molecule will
not react further with other hydrogen or nitrogen atoms.
The molecule can also be shown
without the circles for the shells.
Note the 3
pairs (6 electrons)
shared between the atoms.
Each electron pair is one bond.
This is called a single covalent bond.
Ammonia has three single covalent bonds.
The structural formula of an ammonia molecule is written
There are no ions present (no + or - charges)
in ammonia gas because the electrons are shared,
not transferred from one atom to another.
Ammonia does make some hydroxide ions
when it is dissolved in water to form a weak alkali.
Links Revision Quizzes Revision Questions
gcsescience.com The Periodic Table Index Covalent Bonding Quiz gcsescience.com
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