P1-Topic 2-Bonding, Structure, and The Properties of Matter Flashcards
What is ionic bonding? 3
Ionic bonding is the electrostatic attraction between positive and negative ions
metals,non- metals
It is a relatively strong attraction
How are ionic compounds
held together? 3
They are held together in a giant lattice
a regular structure that extends in all directions in a substance.
Electrostatic attraction between positive and negative ions holds
the structure together
State properties of ionic
substances 3
High melting and boiling point (strong electrostatic forces between oppositely charged ions)
Do not conduct electricity when solid (ions in fixed positions).
Conduct when molten or dissolved in water - ions are free to move
What is important when working out a formula of
an ionic compound? 2
Ionic compounds are electrically neutral,
positive and negative charges balance each other.
What is a covalent bond?
when atoms share one or more pairs of electrons
Describe the structure and properties of simple molecular covalent substances 4
Do not conduct electricity (no ions)
- Small molecules
- Weak intermolecular forces
- Low melting and boiling points
How do intermolecular forces change as the
mass/size of the molecule increases?
They increase.
That causes melting/boiling points to increase as well (more energy needed to overcome these forces).
What are polymers?
Polymers are very large molecules (>100s, 1000s of atoms) with atoms linked by covalent bonds
What are thermosoftening polymers? 2
they melt/soften when
heated
Strong intermolecular forces mean the structure is solid at room temperature.
What are giant covalent substances? Give examples 4
Solids, atoms covalently bonded together in a giant lattice
- ## High melting/boiling points – strong covalent bonds.Mostly don’t conduct electricity- no delocalised electrons
Diamond, graphite, silicon dioxide.
what are the limitations of using dot and cross
diagrams to represent molecules
or giant structures
.xdoesn’t show 3D arrangements of the atoms and electron shells
Doesn’t indicate the relative sizes of the atoms
what are the limitations of using the ball and stick diagram 2
doesn’t show the movement of electrons
atoms placed far apart from each other as in reality the gaps between atoms are much smaller
what are the limitations of using two dimensional diagrams to represent molecules
or giant structures 2
doesn’t show the relative sizes of the atoms and bonds
Cannot give you an idea of the shape of a molecule and what it looks like in 3D space
what are the limitations of using three-dimensional diagrams to represent molecules
or giant structures 2
Only illustrate the outermost layer of the compound
Are difficult and time-consuming to draw
What is metallic bonding?
Forces of attraction between delocalised electrons and nuclei of metal
ions.
Describe properties of
metals 2
High melting/boiling points (strong forces of attraction)
- Good conductors of heat and electricity (delocalised electrons)
- Malleable, soft (layers of atoms can slide over each other whilst maintaining
the attraction forces)
What are alloys? Why are
they harder than pure
metals?2
Alloys:
- mixtures of metal with other elements, usually metals
- different sizes of atoms distorts the layers, so they can’t slide over each other,
therefore alloys are harder than pure metals
What are the limitations of
the simple model? (particle theory) 3
no forces
that all particles are represented as spheres
that the spheres are
solid.
this is not true
What does the amount of energy needed to change state from solid
to liquid or liquid to gas depend on? 3
strength of the forces between the particles of the substance
the type of bonding and the structure of the substance
the stronger the forces between the particles
the higher the melting point and boiling point of the substance
A pure substance will melt or boil at…?
What about the
mixture?
A fixed temperature
A mixture will melt over a range of temperatures.
explain the properties of diamond in terms of its structure and bonding. 4
four, strong covalent bonds for each carbon atom
– very hard (Strong bonds)
– very high melting point (strong bonds)
– does not conduct (no delocalised electrons)
explain the properties of Graphite in terms of its structure and bonding 3
three covalent bonds with
three other carbon atoms,
layers of hexagonal rings
no covalent bonds between the layers
How is graphite similar to metals 2
conduct thermal and electricity
one delocalised electron per each carbon atom
explain the properties of graphene in terms of its structure and bonding. 2
a single layer of graphite
has properties that make
it useful in electronics and composites
