Ionic Bonding
- Created by: EmilyRoseC
- Created on: 22-01-17 11:15
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- Ionic Bonding
- Theory
- They have high melting points so ions are held together by strong attraction
- They are often soluble but not non-polar solvents so we know that the particles are charged
- Don't conduct electricity when solid, only when molten or dissolved = fixed in a solid but free to move in liquid or solution
- Compounds cannot be shaped = strong repulsion between ions, so ionic compounds are brittle = lattice model
- Ions
- Ionic bond = strong electrostatic attraction between two oppositely charges ions
- They do this to gain a full outer shell
- Ions are formed when e- are transferred from one atom to another
- Structures
- Different ionic compounds have different shaped structures, but they're still ionic lattices
- Forms because ions are attracted in all directions to ions of opposite charges
- Ionic crystals are giant lattices = repeated regular structure
- Size
- The ionic radius increases down a group as more electron shells are added
- Isoelectronic ions = different atoms with the same number of electrons
- Ionic radius decreases down a series as the atomic number increases
- Higher number of protons = higher attraction to the nucleus = pulled in further
- Evidence
- Electrolyse a green copper (II) chromate (VI) solution on wet filter paper
- Copper ions move to cathode (end goes blue). Chromate go to anode (yellow)
- Copper (II) ions = blue in solution, chromate (VI) = yellow
- Strength
- Radii
- Smaller ions can pack closer together, which increases the electrostatic attraction, resulting in a higher melting point
- Charge
- Greater charge = stronger electrostatic attraction = higher melting point
- Radii
- Theory
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