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Mapa Mental por Bee Brittain, actualizado hace más de 1 año
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Creado por Bee Brittain
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5.2 Ionic Bonding and Structure
- Ionic Bonding
- Ionic Bonding is the electrostatic attraction between oppositely charged ions
Nota:
- You NEED to know this definition for the OCR chemistry exam - it is on the specification!
- Cations (positive ions)
- Metal Ions
- Na +
- Ca 2+
- Al 3+
- Na +
- Ammonium Ions
- NH4 +
Nota:
- This is just a +1 charge
- NH4 +
- Metal Ions
- Anions (negative ions)
- non-metal ions
- Cl -
- O 2-
- Cl -
- Polyatomic Ions
- NO3 -
- SO4 2-
- NO3 -
- non-metal ions
- Occurs between a metal and a non-metal
- Ionic Bonding is the electrostatic attraction between oppositely charged ions
- Ionic Compounds
- Dot and Cross diagrams
- Outer-shell electrons from a metal atom are
transferred to the outer shell of a non-metal ion
- Positive and negative ions
are formed
- E.g/ Potassium Flouride, KF
- Outer-shell electrons from a metal atom are
transferred to the outer shell of a non-metal ion
- E.g Magnesium Chloride, MgCl2
- Dot and Cross diagrams
- Structure of Ionic Compounds
- Each ion attracts oppositely charged ions in ALL directions
- Giant Ionic Lattice formed containing billions of ions.
- Giant Ionic Lattice formed containing billions of ions.
- E.g/ Sodium Chloride
- Each Na+ ions is surrounded by 6 Cl- ions
- Each Cl- ion is surrounded by 6 Na+ Ions
- Each ion is surrounded by opposite
charged ions, forming a giant ionic lattice
- Each Na+ ions is surrounded by 6 Cl- ions
- Each ion attracts oppositely charged ions in ALL directions
- Melting and Boiling Points
- Almost all ionic compounds are solids at room temperature. This is because
there isn't enough energy to break the strong electrostatic forces of attraction
between the oppositely charged ions in the giant ionic alttice
- High temperatures are needed to break the strong electrostatic forces = most ionic compounds have HIGH boiling points and melting points
- High temperatures are needed to break the strong electrostatic forces = most ionic compounds have HIGH boiling points and melting points
- Almost all ionic compounds are solids at room temperature. This is because
there isn't enough energy to break the strong electrostatic forces of attraction
between the oppositely charged ions in the giant ionic alttice
- Solubility
- Most ionic compounds dissolve in polar solvents, such as
water. This is due to the polar water molecules, which
break down the lattice and surround each ion in solution
- In a compound made of ions with large charges, the ionic
attraction may be too strong for water to be able to break down
the lattice structure = the compound isn't very soluble.
- In a compound made of ions with large charges, the ionic
attraction may be too strong for water to be able to break down
the lattice structure = the compound isn't very soluble.
- Solubility requires two main processes: 1) The ionic lattice must be broken down
2) Water molecules must attract and surround the ions
- Be careful when predicting the solubility of a substance, as the
solubility of a compound in water depends on the relative
strengths of the attractions within the giant ionic lattice and the
attractions between ions and water molecules
- Be careful when predicting the solubility of a substance, as the
solubility of a compound in water depends on the relative
strengths of the attractions within the giant ionic lattice and the
attractions between ions and water molecules
- Most ionic compounds dissolve in polar solvents, such as
water. This is due to the polar water molecules, which
break down the lattice and surround each ion in solution
- Electrical Conductivity
- In a solid state, an ionic compound doesn't conduct electricity. However, once
melted or dissolved in water, the ionic compound does conduct electricity.
- In the solid state ...
- ... the ions are in a fixed position
in the giant ionic lattice
- ... there are no mobile charge carriers
- When liquid or dissolved in water...
- ... the solid ionic lattice breaks down
- ... the ions are now free to move as
mobile charge carriers
- ... the solid ionic lattice breaks down
- ... the ions are in a fixed position
in the giant ionic lattice
- In the solid state ...
- In a solid state, an ionic compound doesn't conduct electricity. However, once
melted or dissolved in water, the ionic compound does conduct electricity.
- Summary
- Ionic compound have high melting and boiling points
- Ionic compounds tend to dissolve in polar solvents such as water
- Ionic compounds conduct electricity when
in liquid state or when in aqueous state
- Ionic compound have high melting and boiling points
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