2.2.2 Bonding & Structure Flashcards
What are the 3 types of bonding
Metallic
Ionic
Covalent
What materials does metallic bonding give rise to
Ones with a giant metallic structure
What compounds does ionic bonding give rise to
Giant ionic lattice
What 2 structures does covalent bonding give rise to
Simple covalent (molecular) structures
Giant covalent (macromolecular) structures
E.g of giant metallic structures
All metals on periodic table
Mg, Na, Zn
What’s giant ionic structure made from
E.gs
Metal + non metal
E.g NaCl, MgO
What’s simple covalent structure made from
E.g
Non metal + non metal
E.g H2O, CO2
What’s giant covalent (macromolecular) structure made from
E.g
Non metal + non metal
C- graphite, C-diamond, SiO2 (sand)
What type of melting + boiling points do simple covalent (molecular) structures have
Why
Low
As they have weak IMFs
What are electrons like in a metal element
They’re delocalised (outer electrons merge + aren’t associated with any one atom no more)
What does metallic bonding involve
A lattice of positive ions surrounded by a ‘sea’ of delocalised electrons e.g Mg
How do positive metal ions act towards the sea of delocalised electrons
They are attracted to the delocalised electrons by electrostatic attraction
Why is metallic bonding very strong and hard to break
As there are no individual bonds to break
Why are metals malleable
As the layers can slide over each other
What must particles be like to conduct electricity (2)
Carry charge
Move freely
Why can metals conduct
As the delocalised electrons are negatively charged and can move
What’s the MP + BP of metals like
High
The atoms are difficult to separate as there is a strong attraction between the metal ions + the delocalised electrons
What’s ionic bonding between
A metal + non metal
What happens during ionic bonding
Electrons are transferred from the metal to the non metal so they can both have a full outer shell
What happens to the metal and non metal in ionic bonding
What do they become
Metal becomes positively charged
Non metal becomes negatively charged
They become ions
What force allows a bond to be formed in ionic bonding
Electrostatic attraction
What’s an ionic bond
Electrostatic force of attraction between positive + negative ions
What forms when ionic bonds are made
E.g
A giant ionic lattice
E.g NaCl
How are the ions positioned in an ionic NaCl diagram
Oppositely charged ions are adjacent to each other
What’s the melting point like in NaCl
Why
High
As each Cl- ion is attracted to Na+ ions so it takes lots of energy to break and is very strong
What would need to happen to melt/break NaCl
Many strong ionic bonds would need to be broken (strong electrostatic attraction) between oppositely charged ions must be broken
When do ionic compounds only conduct
They only conduct when molten/dissolved in water as the ionic bonds are broken and ions are free to move
When don’t ionic compounds conduct
Why
They don’t conduct when solid as the ions can’t move freely although they are charged
What’s covalent bonding between
Non metal + non metal
What happens to the electrons in covalent bonding
They’re shared between the non-metals to gain a full outer shell
What a covalent bond made from
A shared pair of electrons
How does a covalent bond work
The shared electrons in the pair are attracted to the positive nuclei of both atoms
When does a co-ordinate bond form
When both electrons are donated from 1 again (donor atom)
What does co-ordinate (dative) bonding rely on
That the donating atom has an available pair of outer electrons to contribute (lone pair)
What’s the co-ordinate bond represented by
Arrow
What’s the atom that receives the donated electrons in co-ordinate (dative) bonding , said to be
Electron deficient
