Topic 2 Flashcards
(32 cards)
What is ionic bonding?
Ionic bonding is a strong electrostatically charged attraction between a metal and a non-metal where electrons are lost and gained forming ions
Ionic Bond between sodium and chlorine to produce a 2 ions in a ionic bond
What effects the strength of ionic bonding?
Ionic Charge
- The more electrons being lost or gained
- Increases bond strength
Ionic Radius
- The smaller the ionic radius the smaller the distance of the electrons to the nucleus
- Increasing bond strength
How are ions formed (cations and anions)?
Atom loose / gain electron ⇒ Ions
Cation = Positive ion (Electron lost)
Anion = Negative ion (Electrons gained)
What are isoelectric ions?
Isoelectric ions are ions that have the same electronic configuration but different amounts of protons
Example
N^3,O^2-,F^{-},Na^{+},Mg^{2+},Al^{3+}
What are the trends in ionic radii down a group?
As you go down the group ionic radii increases because
- The amount of electron shielding increases
- Increasing the size of the overall ion
- Decrease in nuclear charge
- Meaning the ionic radii increases
What are the trends in ionic radii in isoelectric ions?
As you go along a group of isoelectric ions the ionic radius decreases because:
- The number of protons increase
- The nuclear charge increases
- Pulling the electrons closer to the nucleus
- Decreasing ion size
- Decreasing ionic radii
What are the properties of ionic compounds?
- Strong bonds (High Energy to Break)
- Soluble in water (polar substances) but not in non polar substances (Ions pulled apart by polar molecules)
- Electrical conductor in aqueous and free to carry a charge (Not in fixed position like solid)
What is the migration of ions?
Electrolysed Copper(II) Chromate(VI) on wet filter paper
Green Copper Chromate separates as
- Blue copper cations move to the negative anode
- Yellow chromate anion move to the positive cathode
What is covalent bonding?
A strong electrostatic attraction between two positive nuclei and the shared electrons in a bond between a non-metal and a metal
What is electron repulsion
- The shape of a molecule or ion is caused by repulsion between the pairs of electron surrounding the central atom
- The electron pairs arrange themselves in a way where there is the maximum distance away from each other
- Keeping repulsion between them at a minimum
- Lone pairs have stronger repulsion
What are some examples of the bond angles in molecules and ions?
What is electronegativity?
Electronegativity is the ability of an atom to attract incoming electrons in a covalent bond
What is a dipole?
A separation of charge due to the drift of bonded electrons towards the more electronegative element
What is does it mean a bond is polar?
- Where the difference in electronegativity
- Is enough to cause a uneven distribution of electrons (a dipole) towards the more electronegative element
What does it mean if a bond is non-polar?
- Where the electronegativity difference between the bonded elements is not large enough
- Meaning a uneven distribution of electrons isn’t created
What does it mean if a molecule is polar?
- If a molecule is polar then there is no symmetry in polar bond
- As well as containing any polar bonds
What does it mean if a molecule is non-polar?
- Contains no polar bonds
- Contains polar but they are polyatomic meaning the molecule is symmetrical meaning dipole cancel each other out
Why is water a good solvent?
- Contains hydrogen bonds
- Allows for dissolving of ionic compounds by solvating individual ions
- Allows for dissolving of alcohols by forming hydrogen bonds with their hydroxyl group (-OH)
What can water and alcohols not dissolve?
- Water and alcohols cannot dissolve polar molecules
- No hydrogen bonds present
- Haloalkanes cannot be dissolved
What are non-aqueous solvents used for?
- Used for compounds which have the same type of molecular force
- London + London
- Permanent Dipole + Permanent Dipole
What is metallic bonding?
Metallic bonding is the strong electrostatic attraction between metal ions an delocalised electrons
What is the structure of metallic bonding?
- Lattice of positively charged ions
- Surrounded by a sea of delocalised electrons
- Strong electrostatic forces of attraction between the oppositely charged particles
How does metallic bonding relate to ion charge?
- The greater the charge on the positive ion
- The stronger the attractive force
- As more electrons are added to the sea of delocalised electrons
How does metallic bonding relate to ion size?
- The larger the ion size
- The weaker the attraction from one ion to the other
- Due to the increase in atomic radiius
