AP2 Term exam Flashcards
Covalent bonding
The electrostatic atraction between 2 positive nuclei and a shared pair of electrons.
The number of bonds formed(number of pairs of electrons) is equal to the number of electrons it wants to get
Ionic Bonding
The electrostatic atraction between oppositely charged ions(cation & anion)
Metalic bonding
The electrostatic attraction between positive ions(cations) and delocalised electrons
Halogens(group 7)
- Non-Metals
- Form ionic compunds with metals
- Form covalent compunds with non-metals
- As you go down density and m.p./b.p. increases, reactivity decreases
Alkali metals
- Lose 1 electrons when they form compunds
- As yo go down the outer/valence electrons is further away from the nucleus so it’s easier to lose it. Therefore, reactivity increases as you go down
Lithium
- Li
- Soft, shiny when cut
- Slowly disappears, fizzes, moves around when it reacts with water
Sodium
- Na
- Soft, shiny when cut
- Disappears, fizzes, moves quickly melted in a ball and produces orange flame when it reacts with water
Potassium
-K
-Soft, shiny when cut
-Produces a lilac flame when it reacts with water water
Gasses in the atmosphere
- Nitrogen: 78%
- Oxygen: 21%
- Carbon dioxide: 0.04%
- Others: 0.9%
Dry air is used to measuer composition as non-dry air contains water vapour and other compounds that could alter the measurements. Composition varies by location, time and weather conditions.
Reactivity Series
K - Potassium
Na -Sodium
Li -Lithium
Ca - Calcium
Mg - Magnesium
Al - Aluminium
C - Carbon
Zn - Zinc
Fe - Iron
H - Hydrogen
Cu - Copper
Ag -Silver
Au - Gold
Pt - Platinum
Diamond
Each carbon has 4 covalent bonds
Giant stucture
Used in drill bits and jewlery
M.P./B.P:High
Rigidity: Very strong
Conductivity: No
+ Force: Nuclei
- Force: Pair of electrons
Cause of conductivity: No
Graphite
Each carbon has 3 covalent bonds
Giant Structure
Used in pencil lead and lubricant for machines
M.P./B.P: High
Rigidity: Brittle
Conductivity: When solid
+ Force: Nuclei
- Force: Pair of electrons
Cause of conductivity: Delocalised electron
Covalent Structure
Example: Oxygen gas
M.P./B.P: Low
Rigidity: No
Conductivity: No
+ Force: Nuclei
- Force: Pair of electrons
Cause of conductivity: No
Ionic Structure
Example: Aluminium oxide
M.P./B.P: High
Rigidity: Brittle
Conductivity: When aqueous
+ Force: Positive ion (cation)
- Force: Negative ion(anion)
Cause of conductivity: Free ions
Metalic structure
Example: Titanium
M.P./B.P: High
Rigidity: Malleable
Conductivity: Solid
+ Force: Positive ion(cation)
- Force: Delocalised electron
Cause of conductivity: Delocalised electron
Fullerene
Hollow ball of 60 carbon atoms
Each carbon has 3 covalent bonds
Fixed number of atoms
Reduction
Gaining electrons (losing oxygen)
Oxidation
Losing electrons (gaining oxygen)
Why ionic has high melting point
- Giant ionic structure
- Electrostatic attraction between oppositely charged ions
- Ionic bonds are strong
- Large amount of energy needed to break bonds
Why malleable
- Arranged in layers
- Layers can slide over eachother
Element that has an oxide
- An element that reacts with oxygen / forms and oxide
- That (the element oxide) can react with an acid
Prevent rusting
- Galvanisation / Sacrificial protection
- Barrier methods
Galvanisation
- Sacrificial protection with zinc
- Zing is more reactive than iron
- Zinc reacts with oxygen instead of iron
Sacrificial protection
- Using a more reactive element than iron that will react with oxygen instead
Barrier method
- Stop water or oxygen from reaching the surface of iron
- Painting
- Greasing / Oiling
- Plastic coating
