As chem ocr unit 1 module 2 bonding
- Created by: rosiehawkins
- Created on: 02-12-13 19:29
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- Electron, bonding and structure
- shells and orbitals
- ionisation energies
- The first ionisation energy of an element is the energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions.
- factors affecting it
- Atomic Radius
- Nuclear charge
- Electron shielding
- Electron shielding is the repulsion between electrons in different inner shells. shielding reduces the net attractive force from the positive nucleus on the outer-shell electrons.
- atomic orbitals
- An atomic orbital is a region within an atom that can hold up to two electrons, with opposite spins
- Subshells
- A subshell is a group of the same type of atomic orbitals within a shell.
- A shell is a group of atomic orbitals with the same principal quantum number.
- ionisation energies
- Chemical Bonding
- Ionic bonding
- An ionic bond is the electrostatic attraction between oppositely charged ions
- A giant ionic lattice is a 3-D structure of oppositely charged ions, held together by strong ionic bonds.
- Covalent bonding
- A covalent bond is a bond formed by a shared pair of electrons
- A lone pair is an outer-shell pair of electrons that is not involved in chemical bonding.
- A dative covalent bond is a shared pair of electons which has been provided by one of the bonding atoms only.
- Metallic bonding
- Metallic bonding is the electrostatic attraction between posistive metal ions and delocalised electrons.
- A giant metallic latttice is a 3-D structure of positive ions and delocalised electrons, bonded together by strong metallic bonds.
- Delocalised electrons are shared between more than two atoms.
- Hydrogen bonding
- A hydrogen bond is a strong dipole-dipole attraction between an electron-deficient hydrogen atom on one molecule and a lone pair of electrons on a different molecule.
- Ionic bonding
- Shapes of molecules
- Electronegativity and polarity
- A permanent dipole is a small charge across a bond that results from a difference in the electronegativities of the bonded atoms.
- A polar covalent bond has a permanent dipole.
- Electronegativity is a measure of the attraction of a bonded atom for the pair of electrons in a covalent bond
- A polar molecule has an overall dipole, when you take into account any dipoles across the bonds
- Intermolecular forces
- A permanent dipole-dipole force is a weak attractive force between permanent dipoles in neighbouring polar molecules.
- An intermolecular force is an attractive force between neighbouring molecules.
- Van der waals' forces are attractive forces between induced dipoles in neighbouring molecules.
- Structure
- ionic compounds
- Covalent compounds
- A giant covalent lattice is a 3-D structure of atoms, bonded together by strong covalent bonds.
- A simple molecular lattice is a 3-D structure of molecules, bonded together by weak intermolecular forces.
- shells and orbitals
- Electron shielding
- Electron shielding is the repulsion between electrons in different inner shells. shielding reduces the net attractive force from the positive nucleus on the outer-shell electrons.
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