Chemical Bonding (chpt. 5) Flashcards
Compound
A substance made up of two or more different elements combined together chemically
Octet rule
When bonding occurs, atoms tend to reach an electron arrangement with 8 electrons in the outer shell
Exceptions to octet rule
Transition metals
Elements near helium - full shell of 2
Ion
Charged atom or group of atoms
Ionic bond
The force of attraction between oppositely charged ions in a compound
Ionic bonds are always formed by the complete transfer of electrons from one atom to another
Sodium chloride crystal structure
Ionic crystal lattice
Forms crystals because positive ions attract negative ions in all directions
DRAW
Na +
Cl -
Properties of transition metals
- Variable valency
- Forms coloured compounds
- Used as catalysts
Transition metal
One that forms at least one ion with a partially filled d sublevel
Molecule
A group of atoms joined together
Smallest particle of an element or compound that can exist independently
Electronegativity
The relative attraction that an atom in a molecule has for the shared pair of electrons in a covalent bond
Electronegativity
The relative attraction that an atom in a molecule has for the shared pair of electrons in a covalent bond
Inter molecular bonding
Forces of attraction that exist between molecules
E.g. van der waals, dipole-dipole, hydrogen bonding
Van der waals
Weak attractive forces between molecules resulting from the formation of temporary dipoles. Only force of attraction between non-polar molecules
Weakest
Temporary dipole-dipole
Non-polar molecules
Higher boiling point as number of electrons increases
Dipole-dipole
Forces of attraction between negative pole of one polar molecule and the positive pole of another polar molecule
Stronger than van der waal
Polar-covalent molecules
Hydrogen bonding
NOF
3 most electronegative elements
Strongest
Hydrogen is slightly positive and attracted to slightly negative other element
High boiling points
