Chem - Chemical Bonding And Structure Flashcards
What types of elements form an ionic bond?
Metals and non-metals
What types of elements form a covalent bond
Non-metals and non-metals
What types of elements form a metallic bond?
Metals and metals
How does ionic bonding take place?
The outer shell electrons of the metal are transferred to the non metal to produce a full outer shell of electrons for both, however, losing or gaining electrons will form negative and positive ions bonding the two together
What is an ionic compound?
A giant structure of ions held together by electrostatic attractions between oppositely charged ions
What is a limitation of dot cross diagrams
Doesn’t indicate the relative size of atoms
What is an empirical formula?
An oversimplified version of the molecular formula eg.
Molecular formula: N2O4
Empirical formula: NO2
What are properties of ionic compounds
- High melting and boiling points due to the strong electrostatic attraction between ions
- When melted or dissolved conduct electricity because the ions are free to move so charge can flow
What are covalent bonds?
Where two atoms share electrons to produce what they think is a ‘full outer shell’
What are some properties of small molecules?
- Weak intermolecular forces so low melting and boiling points
- Do not conduct electricity as molecules do not have an overall charge
- Larger molecules have larger intermolecular forces and so will have higher boiling and melting points
What type of bonding holds together polymers?
Covalent bonding
What are two examples of giant covalent structures?
Diamond and graphite
Why does graphite conduct electricity?
Each carbon atom forms three covalent bonds and so one electron from each carbon atom is delocalised
What is graphene
A single layer of graphite which has properties useful in electronics
What are fullerenes?
Molecules of carbon atoms with hollow shapes such as carbon nanotubes