what is the structure of ionic compounds?
arranged in a giant ionic crystal lattice
held together tightly as oppositely charged ions attract one another strongly
name physical properties of ionic compounds (1)
high melting and boiling points
- strong electrostatic forces of attraction between oppositely charged ions
- a large amount of heat energy required to overcome them
- non-volatile
name physical properties of ionic compounds (2)
soluble in water
- water molecules are attracted to ions
- weakens the electrostatic force
- ions pulled from solution, dissolve in aqueous solution
insoluble in organic solvents
- no water present, remain tightly held in ionic crystal lattice
name physical properties of ionic compounds (3)
conduct electricity in molten and aqueous solution
- free-moving ions in aq solution, cations and anions are free to move and are able to conduct electricity
what is the structure of covalent compounds ?
simple molecular structure (SMS)
giant molecular structure (GMS)
name physical properties of SMS (1)
low melting and boiling points
- held by weak intermolecular forces of attraction
- can be easily overcome
- volatile
name physical properties of SMS (2)
inosluble in water and soluble in organic solvents
name physical properties of SMS (3)
do NOT conduct electricity
name physical properties of GMS (1)
high meting and boiling points
- large number of atoms held together by strong covalent bonds
- requires a lot of energy to break
- solids at rtp
name physical properties of GMS (2)
do NOT conduct electricity ( except graphite )
name physical properties of GMS (3)
insoluble in both water and organic solvents
diamonds
- covalently bonded to 4 other carbon atoms
- all outer electrons r used for bonding ( CANNOT conduct electricity )
- no free electrons
graphite
- covalently bonded to 3 other atoms
- soft and slippery, layers of carbon atoms, slide easily over one another when force is applied
- has one free moving electron that allows it to conduct electricity
metallic bonding
- outermost electrons form a sea of delocalised electrons
surrounding the positive metal ions - free to move around the metallic lattice structure
- strong electrostatic forces of attraction between positively charged metal ions and negative electrons
physical properties of metals (1)
high densities melting and boiling points
- packed tightly in layers and are held by strong metallic bonds
physical properties of metals (2)
good conductors of heat and electricity
- outermost electrons break away easily and move freely, mobile electrons allow the metal to conduct electricity
- heat energy is easily transferred within the lattice structure
physical properties of metals (3)
malleable and ductile
- can be hammered into diff shapes and drawn into wires without breaking
