Bonding and Structure 2 Flashcards
Why does giant ionic lattices
conduct electricity when liquid
but not when solid?
In solid state the ions are in fixed positions and thus cannot move. When they are in liquid state the ions are mobile and thus can freely carry the charge
Giant ionic lattices have high
or low melting and boiling
point? Explain your answer
They have high melting and boiling point
because a large amount of energy is
required to overcome the electrostatic
bonds
In what type of solvents do
ionic lattices dissolve?
Polar solvents
E.g water
Why are ionic compounds
soluble in water?
Water has a polar bond. Hydrogen atoms have a + charge and oxygen atoms have a - charge.
What is it called when atoms
are bonded by a single pair of
shared electrons?
Single bond
How many covalent bonds
does carbon form?
4
How many covalent bonds
does oxygen form?
2
What is the effect of multiple
covalent bonds on bond
length and strength
Double/triple bonds exert greater
electron density therefore the attraction
between nucleus and electron is greater
resulting in a shorter and stronger bond.
What is a lone pair?
Electrons in the outer shell that are not
involved in the bonding
What is formed when atoms
share two pairs of electrons?
Double bond
What is formed when atoms
share three pairs of electrons?
Triple bond
What is a dative covalent
bond?
A bond where both of the shared
electrons are supplied by one atom
How are oxonium ions
formed?
Formed when acid is added to water,
H3O+
What does the expansion of the octet mean?
When a bonded atom has more than 8
electrons in the outer shell
What are the types of covalent
structure?
● Simple molecular lattice
● Giant covalent lattice
Describe the bonding in simple
molecular structures
Atoms within the same molecule are held
by strong covalent bonds and different
molecules are held by weak
intermolecular forces
Why do simple molecular
structures have low melting
and boiling point?
Small amount of energy is enough to
overcome the intermolecular forces
Can simple molecular
structures conduct electricity?
No, they are non conductors
Why do simple molecular
structures not conduct
electricity?
The have no free charged particles to
move around
Simple molecular structures
dissolve in what type of
solvent?
Non polar solvents
Give examples of giant
covalent structures
● Diamond
● Graphite
● Silicon dioxide, SiO2
List some properties of giant
covalent structures? (3)
● High melting and boiling point
● Non conductors of electricity, except graphite
● Insoluble in polar and non polar solvents
How does graphite conduct
electricity?
Delocalised electrons present between
the layers are able to move freely
carrying the charge
