2D Flashcards
Metallic bonding
Electrostatic attraction between positive metal ions and negative delocalised electrons
What are delocalised electrons
Metals have a relatively low 1st ionisation energy, the valence electrons are held loosely and in a metallic lattice, each atom loses its valence electron/s which then extend through the lattice occupying a new set of energy levels. These are said to be delocalised
Ionic bonding
electrostatic attraction between the positive cations and negative anions
covalent bonding
Electrostatic attraction between the shared pair of electrons and the nuclei of the bonded atoms
Intermolecular bonding
Electrostatic attraction between dipoles on molecules
How many bonds can Group 1/ Group 7 make
1
How many bonds can Group 6 make
double bond
How many bonds can Group 5 make
Triple bonding
Octet rule
When an atom of an element has 8 electrons in its outer shell i is said to have an octet
When does the octet rule not work?
- Atoms in elements tat are in Group 3 or higher - have access to 3d subshell which holds 10 electrons
- unpaired electrons can pair up - max number of electron pairs in an outer shell is number of electrons in outer shell
What is a dative covalent bond?
A covalent bond where both of the electrons come from a single bond
Eg : in an ammonium ion where in ammonia, Nitrogen has 2 free electrons that can form a bond with a hydrogen ion with no electrons
What is needed for a dative covalent bond to form
- The acceptor atom must be electron deficient - available orbitals for electrons to occupy
In what way is a dative and covalent bond the same
- Dative and Covalent bonds are exactly the same
- Same length
- Same average bond enthalpy
What is a lone pair
A pair or electrons not used in bonding on the outer shell
What is a Polyatomic ion
A group of atoms with a charge - For example a carbonate ion
What is a giant ionic lattice
A regular 3D of oppositely charged ions, held together by electrostatic attractions
Features of a giant ionic lattice
- Conducts electricity when molten or aqueous - not solid
- High MP, BP
- Ionic bonding
Giant metallic lattice
A regular 3D arrangement of positive ions and delocalised electrons
Features of Giant metallic lattice
- High MP and BP
- Conducts electricity when solid or liquid
- Metallic bonding