1C Structure and Bonding Flashcards
(26 cards)
What are intramolecular bonds?
Bonds within a molecule.
For example covalent bonds.
What are intermolecular forces (bonds)?
Forces of attraction between molecules.
Referred to as Van der Waals forces.
Name the 3 types of Van der Waals forces.
- London dispersion forces (ldf)
- Permanent dipole to permanent dipole forces (pd:pd)
- Hydrogen bonding
Define the term “metallic bond”.
The electrostatic force between positively
charged ions and delocalised outer electrons.
Weak or strong?
Metallic bonds
Strong
Weak or strong?
Covalent bonds
Strong
Weak or strong?
Ionic bonds
Strong
Comment on strength of:
London dispersion forces (LDF’s)
Weakest intermolecular forces of attraction between molecules.
Comment on strength of:
Permanent dipole-permanent dipole (pd-pd)
Weak intermolecular forces of attraction between molecules.
(Stronger that LDF’s, weaker than H-bonding)
Comment on strength of:
Hydrogen bonding (H-bonding)
Intermolecular force. Stronger than LDF’s and pd-pd.
Define the term “ionic bond”.
The electrostatic force of attraction between
positively and negatively charged ions.
Ionic compounds conduct when…
Molten or in solution. Not when solid as ions (charged particles) are not free to move.
Metallic compounds conduct when…
Solid or molten as delocalised electrons (charged particles) are always free to move.
Define the term “covalent bond”
The electrostatic force of attraction between
positively charged nuclei and negatively charged outer electrons.
What structure do ionic substances have?
3D Lattice structure.
What structures can covalent substances have?
Molecular - H2, CH4, C60.
Network - Diamond, Graphite.
Why do Covalent network structures have high mpts and bpts?
Covalent networks have very high melting and boiling points as
many strong covalent bonds need to be broken in order to change
state.
Covalent substances do not conduct because…
They have no free moving charged particles.
One covalent network substance that conducts is called…
Graphite. It has one delocalised electron per atom that is free to move within the structure.
What is polar bonding?
Polar covalent is
formed in compounds between different non-metal elements with different electronegativities.
What is non-polar covalent bonding?
Pure covalent bonding is
formed in elements or compounds between non-metal atoms with the same or similar electronegativities.
The larger the difference in electronegativity between two atoms means the compound is likely to be….
Ionic in nature.
The smaller the difference in electronegativity between two atoms means the compound is likely to be….
Covalent in nature.
Permanent dipoles are caused by…
atoms having a significant difference in electronegativity (polar bond) leading to ends being permanently charged.
