Chemical Bonding Flashcards
What is a bond between two non-metals called
A covalent bond
Define compound
A chemically bonded substance made of 2 or more elements with fixed proportions
What is a diatomic molecule
A molecule made of two atoms
What is covalent bonding in terms of electrons
A chemical bond through shared electrons
What is covalent bonding in terms of components
Two or more non-metals
What forces are in lattice covalent bonds
Strong covalent bonds
Molecules can only have one type of bonding and structure, which is:
discrete covalent
What forces are there INSIDE discrete covalent molecules
Strong Covalent Bonds
What forces are there BETWEEN discrete covalent molecules
Weak Inter Molecular Forces
How big is a lattice structure
infinite
How big is a discrete covalent structure
Very small, sometimes only 2 atoms.
Example question 1: How many electrons are shared in H2
2 electrons (1 pair)
Example question 1: How many electrons are shared in N2
6 electrons (3 pairs)
What is the number of shared electron pairs based on
The combining power of the atoms
Example question 1: describe the shared electron pairs in NH3
3 H have a pair of shared electrons with one N
H N H
H
Example question 1: describe the shared electron pairs in CO2
2 O have 2 pairs of shared electrons with one C
O=C=O
How are covalent bonds drawn
Like a venn diagram, with the number of pairs of shared electrons drawn in the center. ONLY the OUTER energy level is drawn.
What are the melting points of discrete covalent structures
Very low
Why are the melting points of discrete covalent structures low
Because they have weak IMFs, which do not require lots of force to break apart.
Discrete covalent structures are soluble in ___________
Nothing
Discrete covalent structures are conductive in what forms?
None.
Why don’t discrete covalent structures conduct?
Because they have no charged particles
What is a bond between a metal and a non-metal called
Ionic Bond
What are the forces in ionic bonds
electrostatic forces
What is an ionic lattice structure
A structure of alternating atoms of positive and negative charges.
What happens physically for an atom to become an ion?
It either gains or loses electron(s)
What happens physically for an ionic bond to occur
One atom takes electron(s) from another atom
How are ionic compounds drawn
The ion version of the atom (having lost or gained e-(s) with all its energy levels that contain e-(s), in [] with its charge at the top right corner, and ……. (electrostatic force) between the ions.
How is charge written
Magnitude of charge followed by type of charge (2+, 3-, +, 4-)
What is charge based on?
How many e-(s) an atom has to lose to have a full outer energy level
Ionic substances are soluble in _______
water
The melting points of ionic substances are _______
very high
Why are the melting points of ionic substances high?
Because strong electrostatic forces require lots of energy to break apart.
Ionic substances conduct as _______
liquid (l) or aqueous (aq)
How do ionic substances conduct (What carries charge?)
Electrons carry charge
Why do ionic substances conduct as fluids except gases
They don’t conduct as gases, because gases can’t carry charge, and not as solids, because the electrons can’t move to carry charge
Are ionic substances malleable
No
Why aren’t ionic substances malleable?
Because if the atoms are moved from their pattern of opposing charges, and atoms have the same charges, they will repel each other and therefore break apart.
What are cations
Positive ions (Having lost electrons)
What are anions
Negative ions (Having gained electrons)
Why does graphite conduct electricity, but diamond doesn’t?
Because graphite has seas of delocalised electrons which can move and carry charge
What are the forces in lattice covalent structures
Strong covalent bonds
Is graphite malleable
Yes
Why is graphite malleable
Because it is in layers which can easily maintain their shape when bent or hit
Are lattice covalent structures GENERALLY malleable
No
Why are lattice covalent structures brittle
Because if one bond breaks, many more tend to break with it
What are lattice covalent structures soluble in
Nothing
Melting points of lattice covalent structures are _____
Very high
Why are melting points in lattice covalent structures high
Because it requires a lot of energy to break so many strong covalent bonds
What is it called when metals bond with metals
Metallic bonding
What is it called when two DIFFERENT metals are chemically bonded
An alloy
Are metals malleable
Yes
Why are metals malleable
Because they are in layers which can easily maintain their shape when bent or hit
How do metals carry charge
Through delocalized e-(s)
Metals conduct as ______
solids
What does metallic structure look like
There are layers of the metal, arranged in a pattern, altetnating with layers of delocalised e-s in a random pattern (same as graphite)
