2.2 Flashcards
Electron configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d10 7s2 7p6
4s fills before 3d but empties before 3d
Electron structure
S orbitals: one orbital 1s2 (sphere)
P orbitals: three orbitals 2p6 (dumbbell)
D orbitals: five orbitals 3d10
F orbitals: seven orbitals 4d14
Ionic bonding
- Metal/non-metal
- Electrostatic attraction between +ve and -ve ions
- Electrons transferred
Properties:
• conduct when molten or dissolved
• high mpt and bpt
• tend to dissolve in water
Covalent bonding
- between non-metals
- shared pair of electrons
- strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms
- dative bond = both from one atom
- avg bond enthalpy = bond strength
- > giant covalent
- > simple molecular (London forces,H-bonds,dipole-dipole)
Shapes of molecules; Electron pair repulsion theory
- electron pairs determine shape of molecule or ion
- electron lairs repel each other as far apart as possible
- held in a definite shape
- lone pairs repel more than bonded pairs
Linear
2 bonded, 0 lone
180 degrees
Trigonal planar
3 bonded, 0 lone
120 degrees
Tetrahedral
4 bonded, 0 lone
109.5 degrees
Octahedral
6 bonded, 0 lone
90 degrees
Trigonal pyramidal
3 bonded, 1 lone
107 degrees
Non-linear
2 bonded, 2 lone
104.5 degrees
IM forces; permanent dipole-dipole interactions
s+ve
s-ve
Weak electrostatic forces determined by electronegativity
IM forces; induced dipole-dipole interactions
London forces
ALL atoms experience it
Electrons constantly moving within orbitals = temporary dipole
IM forces; Hydrogen bonding
Permanent dipole between Hydrogen and NOF
Must be a LONE PAIR E-
Hydrogen bonding in water
Ice less dense than water
• H-bonds gold molecules apart in open lattice
• Molecules further apart
• Floats, less dense
= high mpt and bpt
= high surface tension
