Structure and Bonding Flashcards
Ionic Bonding
- An electrostatic attraction between 2 oppositely charged ions
- Happens between metals and non-metals
Properties of Ionic Compounds
- Always solid at room temperature
- Conduct electricity when molten or dissolved as ions are free to move and carry charge
- High melting and pointing points as lots of energy is needed to break strong electrostatic forces of attraction between the ions
- Brittle and shatter easily when the layers of alternating charge are distorted in a lattice. The charges repel causing the lattice to fragment
Covalent Bonding
- Electrostatic attraction between the nucleus of an atom and a shared pair of electrons
- Happens between non-metals
Double Bond
- When the atoms each share 2 electrons with each other
- E.g. Carbon Dioxide
Triple Bond
- When the atoms each share 3 electrons with each other
- E.g. Carbon Monoxide
Properties of Simple Molecular Compounds
- Low melting and boiling points due to weak Van Der Waals forces
- Don’t conduct electricity because there are no particles that can carry charge
Dative Covalent Bond/Coordinate Bond
- A bond where both electrons in the shared paired are supplied by the same atom
- Represented using an arrow
- Once a dative bond has formed, it is treated as a standard covalent bond as it reacts in the same way as one
Examples of Dative Covalent Bonds
- NH3 and H+ become NH4+
- A double bond between carbon and oxygen becomes a triple bond (oxygen shares an extra lone pair so carbon also has a full outer shell)
Metallic Bonding
- A lattice of positively charged ions surrounded by a sea of delocalised electrons
- Strong electrostatic forces of attraction between the oppositely charged ions
- Occurs between metals
Properties of Metallic Structures
- Good conductors of electricity/heat
- Malleable
- Ductile
- High melting and boiling points
Explanation of Metallic Structure Properties
- Good conductors of electricity/heat as they have delocalised electrons that can carry charge through the structure
- Malleable and ductile as the layers of positive ions are able to slide over one another
- High melting/boiling points due to strong electrostatic forces of attraction which require lots of energy to break
Electronegativity
- The tendency of an atom to attract a bonding pair of electrons in a covalent bond
Factors impacting Electronegativity
- Atomic Radius
- Distance from nucleus
- Nuclear Charge
- Electron Shielding
How does Atomic Radius impact Electronegativity?
A smaller atom has a higher electronegativity as the pair of electrons is closer do the nucleus so there is less shielding
How does Nuclear Charge impact Electronegativity?
Increased nuclear charge increases electronegativity as the more protons there are, the stronger the attraction to the shared pair of electrons