(U1) Structure Flashcards
1
Q
How are ionic compounds structured?
A
- Arranged in a Giant ionic lattice,
- where the electrostatic forces of attraction hold the ions in rows
- on every side of each ion there is an oppositely charged ion
2
Q
What are the properties of ionic compounds? (3)
A
- high m.p. And b.p.
- only conduct electricity when molten or in solution
- physically hard
3
Q
What is the co-ordination of the lattice of NaCl?
A
6-6 co-ordination
4
Q
What are allotropes? (3)
A
- different forms
- of the same element
- in the same physical state
5
Q
Name 3 allotropes of carbon.
A
- diamond
- graphite
- graphene
6
Q
What are the physical properties of Ionic compounds? (4)
Explain each in detail
A
- High m.p and b.p:
- The bonds within the ions are extremely strong
- need a substantial amount of energy to break the strong bonds
- Soluble in water:
- Ionic solids are dipolar
- attracted by polar water molecules
- Good conductors of electricity and heat when molten or in solution:
- the ions are free to move and carry charge.
- When dissolved, ionic compounds such as sodium chloride can cause aqueous solutions to boil faster
- Physically hard:
- bonds require a substantial amount of force to break
7
Q
Describe the structure and bonding in diamond
What are the properties of diamond? (3)
Explain each
A
- Each carbon atom makes 4 strong covalent bonds
- Tetrahedral structure (3d giant covalent)
- high m.p and b.p - substantial amount of energy required to break covalent bonds
- No electrical conductivity - all electrons involved in bonds
- physically hard - substantial amount of force required to overcome covalent bonds
8
Q
Describe the structure and bonding in graphite
What are the properties of graphite? (3)
Explain each
A
- giant covalent structure
- hexagonal layers separated by Van der Waals forces
- each carbon bonds 3x - 1 free electron per each carbon
- good conductor of electricity - delocalised electrons free to move and carry a charge
- high m.p and b.p - substantial amount of energy required to break covalent bonds
- physically brittle - small amount of force required to overcome Van der Waals
9
Q
What are the properties of molecular covalent structures? (5)
Explain.
A
- low m.p and b.p:
- non-substantial amount of thermal energy required to overcome Van der Waals
- Usually soft and brittle:
- Van der Waals easily overcome by force
- Insoluble in water:
- hydrogen bonds are stronger than bonds formed with molecular covalent structures
- Soluble in organic liquids:
- non-polar ones don’t have hydrogen bonds
- instead have weak intermolecular forces
- therefore molecular covalents can bond
- Never conduct electricity:
- all electrons used in covalent bonds
- no ions