Structure and Bonding broad sheet questions Flashcards
(32 cards)
What is an ion?
An atom with a charge.
What is covalent bonding?
This is where atoms share electrons to obtain a full outer shell.
This is where 2 NON METALS JOIN.
What holds atoms together in a covalent bond?
The electrostatic attraction between positive nucleus’ and the shared pair of electrons.
How are ions formed?
Atoms that loose electrons (metals) gain a positive charge.
Atoms that gain electrons(non-metals) gain a negative charge.
IONIC BONDS FORM BETWEEN NON-METALS AND METALS.
Why do ionic compounds have a high melting point?
Because regular arrays of positive and negative ions contain many strong electrostatic attractions which require a large amount of heat energy to over come. (break)
Describe the difference between an allotrope and an isotope?
Allotrope: Different structures of the same element.
Isotope: Different mass atoms of the same element.
Explain why metals are malleable?
Because layers of electrons can slide over each other. The ‘sea of electrons’ can change shape but does not break which is why it can bend.
Name some properties of metals:
- solid
- high melting point
- shiny
- high density
- Good conductor of heat & electricity
- malleable
- ductile
Property’s of non-metals:
- solid liquid or gas
- low melting points
- Brittle
- low density
- poor conductor of heat & electricity
What is metallic bonding?
When metals contain a regular array of positive metal ions surrounded by delocalised ‘sea of electrons’.
OOOOOOO
OOOOOOO (Positive ions with electrons
OOOOOOOO. Surrounding it)
What is a metallic bond?
A metallic bond is the electrostatic attraction between a positive ion and the delocalised sea of electrons.
2 METALS FORM A METALLIC BOND.
Explain why metals are good condoctors of electricity?
Metals have electrons which are free to move in the delocalised ‘sea of electrons’ so as moving electrons can carry and transfer charge it makes metals conduct.
How does the charge on the metal ion effect strength and conduction of metal?
Higher charged ion = more delocalised electrons which= stronger metallic bonds and better conductor of electricity.
What are the 3 types of chemical bonds and what atoms do they form between?
Ionic bonds (metal &a non-metal)
Covalent bonds (non-metal & non-metal)
Metallic bonds (metal & metal)
Explain why simple covalent molecules do not conduct electricity ?
Simple molecules have no charged particles to carry current. Electrons are involved in covalent bonds between molecules and cannot be used to carry charge.
What is a molecule?
A small group of atoms that go around each other.
What are simple molecular compounds?
Simple molecular compound have strong covalent bonds holding the atoms together in the molecule. As they normally form gases and liquids they have weak intermolecular forces between the molecules.
Properties: gases or liquid, low melting point, do not conduct electricity.
Explain why graphite conductus electricity and diamond doesn’t?
Because Graphite forms a layered structure. Between the layers are week intermolecular forces containing free electrons which can move between the layers.
All the electrons in diamonds are involved in strong covalent bonds so do t have free electrons to carry charge.
Describe the structure of diamond
Every carbon atom is bonded to 4 other carbon atoms with a strong covalent bond. This looks like a giant structure of tetrahedral carbons.
Describe the structure of graphite
Every carbon atom is bounded to 3 other carbon atoms with strong covalent bonds to form hexagons which join to form layers. These layers are held together with week forces.
What is a polymer and how are they made?
Polymers are very large molecules that form chains. They are made in polymerisation reactions from monomers.
Monomer -> polymer
How and why are the properties of polymers different to those of simple molecules?
How: polymers are low melting point solids which can be moulded into shapes. Simple molecules tend to be liquids or gas.
Why: Polymers are very large molecules with large intermolecular forces. They form chains which get tangled up.
Describe the structure of an ionic compound.
Ionic compounds form lattices which are regular arrays of positive and negative ions held together with strong electrostatic attractions(ionic bonds) to give a giant structure.
ALL IONIC COMPOUNDS FORM LATTICES AND CRYSTALS WHEN SOLID.
What is the difference in bonding between a simple covalent molecule and a giant covalent structure?
Simple covalent molecule: Atoms are held together with covalent bonds in molecules. Molecules are held together with weak intermolecular forces .
Giant covalent structure: every atom is held to every other atom with a strong covalent bond. This creates a giant lattice all held together with strong covalent bonds.
