Structure and bonding Flashcards
Why does elements from group 3,4 and 5 not form ions easily?
Need to gain or lose a larger number of electrons which requires more energy
How are ionic binds made?
- opposite charges
- attracted each other by electrostatic forces
Giant ionic lattice
Each atom is attracted to all those around it
Properties of ionic compunds
- high melting and boiling points
- as there are a lot of ionic bonds that
are really strong so it requires a lot
of energy to break them
- as there are a lot of ionic bonds that
- conduct electricity (only when melted
or dissolved in water
Why cant ionic compounds conduct electricity when a solid?
Fixed structure so no charged particles can move
How can ionic compounds when aqueous conduct electricy?
the charged ions are free to move about while carrying electric charge
Hydroxide ion
OH-
Sulfate ion
SO4-2
nitrate ion
NO3-
Carbonate ion
CO3-2
Ammonium ion
NH4+
ionic compound structue
- giant ionic lattice structure
- ions form a closely packed regular
lattice arrangement - held together by strong electrostatic
forces of oppositely charged ions
simple molecular substances
- atoms within the molecules are held
together by very strong covalent
bonds - however forces of attraction between
molecules are very weak (weak inter-
molecular forces)
What are some examples of simple molecular substances
- ammonia
- chlorine
What are some examples of giant covalent structures
- diamond
- silicon dioxide
- graphite
simple molecular substances properties
- low melting and boiling points
- gases and liquid and room temp
- as molecule gets bigger the strength of
the inter molecular forces increases- so more energy is needed to break
them
- so more energy is needed to break
- dont conduct electricity because they
arent charged- no delocalised electrons or ions
Why does the boiling point increases as you go down the group (covalent bond)
The molecules get larger so there is more intermolecular forces between them
Allotropes
Different structure form of the same element in the same physical state
Allotropes of carbon
- diamond
- graphite
- fullerenes
Giant Covent structure
Carbon arranged in regular repeating lattic
Diamond
- cant conduct electricity
- high melting and boiling point
- each carbon atom is bonded to 4 other carbon atom
- regular 3D lattice very strong
Graphite
- carbon atom bond to 3 other atoms
- softer
- 2D layers made up of repeating hexagon
- conduct electricity
Fullerenes
Allotropes of carbon made by bending sheets of graphene into hollow structures
Fullerenes uses
- deliver medicine around body
- catalysts in chemical reactions
Why are fullerenes useful?
They have a high surface area to to volume ratio
Alloys
Made up of different size of elements to have a stronger metal
Harm of sunscreen
- they may renter cells damaging our DNA
- cause harm to oceanic environments
Electrolysis
Separate the elements in insoluble ionic compounds
