3.1 ionic bonding Flashcards
Define ionic bonding.
Ionic bonding is the electrostatic force of attraction between oppositely charged ions formed by electron transfer.
Molecular ions:
Hydroxide = OH-
Nitrate = NO3-
Ammonium = NH4+
Sulfate = SO42-
Carbonate = CO32-
What ions does group 1 form?
Group 1 elements lose 1 electron, forming 1+ ions.
What ions does group 2 form?
Group 2 elements lose 2 electrons, 2+ ions.
What ions does group 3 form?
Group 3 elements lose 3 electrons, forming 3+ ions.
What ions does group 4 form?
They rarely form ionic bonds, typically they form covalent bonds.
What ions does group 5 form?
Group 5 elements gain 3 electrons, forming 3- ions.
What ions does group 6 form?
Group 6 elements gain 2 electrons, forming 2- ions.
What ions does group 7 form?
Group 7 elements gain 1 electron, forming 1- ions.
What is an ionic compound?
An ionic compound is a crystalline solid that are held together by ionic bonds, which can form giant ionic lattices.
Formulas of ionic compounds.
1) Write the two ions: Ca2+ and O2-
2) Swap the charges: Ca2- and O2+
3) Drop the charges: Ca2 and O2
4) Simplify to lowest whole number if needed: Ca2O2 simplifies to CaO
What is the structure of an ionic compound?
Ionic compounds form giant ionic lattices where each ion is surrounded by oppositely charged ions.
What are the properties of an ionic compound?
- Have high melting and boiling points
- They are soluble
- Can conduct electricity when molten or in solvent
- They are hard and brittle
Why do they have high melting and boiling points?
The electrostatic forces holding the ionic lattice together are strong and require a lot of energy to overcome.
How are they soluble in water?
The positive and negative ends of water attract the oppositely charged ions in an ionic compound allowing it to be fully dissolved.
How can they conduct electricity when molten (melted) or when in solvent?
The ions are separate when molten or in solvent and are no longer held in a lattice. They are free to move and can carry a flow of charge and create an electrical current.
Why do they not conduct electricity when solid?
The ions in the lattice are held in place and cannot move around to carry a charge.
Why are they brittle?
When the layers of alternating charges are distorted the charges will repel therefore breaking apart the lattice into fragments.