Types of Covalent Structures Flashcards
Atoms can share electrons to form:
covalent bonds
Covalent substances that only contain a few atoms are called?
simple molecular substances.
covalent substances with millions of atoms are called?
giant covalent substances
an example of a giant molecular structure?
Silicon dioxide (silica)
In simple molecular substances, the individual molecules are held together by?…
weak intermolecular forces exist between the molecules.
(The atoms within a molecule are held together by strong covalent bonds)
can intermolecular forces in simple molecular substances be broken down at relatively high/low temperatures?
they can be broken at relatively low temperatures.
at what state do simple molecular substances exist at room temp?
simple molecular substances exist in the gaseous state at room temperature.
at what state does chlorine exist at room temperature?
gas
at what state does bromine exist at room temp?
liquid
at what state does iodine exist at room temp?
solid, gives off purple flames
why are the halogens, chlorine, bromine and iodine different states at room temp?
they have different melting and boiling points. As you go down group 7, the atoms (thus the molecules) get larger. This means there will be more intermolecular forces, and so more energy will be required to break them.
two properties of simple molecular substances:
- Low boiling points
- Unable to conduct electricity
simple molecular substances:
- Strong covalent bonds between the atoms of each molecule.
- Weak intermolecular forces between molecules.
- Low melting and boiling points (so normally gaseous as room temperature).
- Cannot conduct electricity.
examples of giant covalent structures.
- diamond and graphite
their atoms are arranged in a regular repeating lattice structure with many multiple covalent bonds between each atom.
Do giant covalent structures have high or low melting points?
- high
(the atoms are all held together by strong covalent bonds which require a large amount of energy to break.)
