2. Bonding and structure ( IONIC) Flashcards
What is ionic bonding
The strong electrostatic attraction between 2 oppositely charged ions
What structure do ionic compounds form
Giant ionic lattices
What is ionic bonding formed from
The transfer of electrons between metals and non metals in order to gain a full outer shell
Give 4 properties of ionic compounds
High melting and boiling points
Brittle and easily cleaved
Soluble in water
Conduct electricity when molten or aqueous
Explain why ionic compounds are brittle
They are brittle because when the ions are forced out of position, like charges line up and cause repulsion and cracking of the ionic compound.
Explain why an Na ion has a 1+ charge
The atom has lost an electron so there is now 10 electrons but still 11 protons so an overall 1+ charge
How do ions size change compared to their atoms
- positive ions (cations) get smaller
- negative ions (anions) get bigger
Give 2 main properties that affect the strength of electrostatic attraction in ionic compounds so therefore the melting point
Size of the charge - greater charge = stronger electrostatic force of attraction (more energy required to overcome..)
Ionic radius (size of ion) - smaller sized ions packed more closely = stronger electrostatic attraction
–> smaller sized ion + greater charge = high charge density
Trends in ionic radii for isoelectric ions
- same number of electrons yet differing proton numbers
- as proton number increases the ionic radius decreases as there is a greater nuclear charge on the same amount of electrons
Trends in ionic radii (down the group)
The ionic radius increases down a group as there are more electron shells
Give an experiment to show the evidence for charged particles
Electrolysis of copper (II) chromate (IV)
chopper chromate solution = green
when a current is passed through solution:
BLUE Cu 2+ ions = attracted to negative cathode
YELLOW CrO4 2- ions = attracted to positive anode
