CHEM1101 Lecture Notes - Spring 2018 Lecture 1 - Lewis structure, Covalent bond
Periodic Table
Anomalies:
Some irregularities occur when there are enough electrons to half fill s & d orbitals on a given
row. (not universal for all anomalies)
Chromium:
⎯ E- configuration: [Ar] 4s13d5
Rather than expected:
[Ar] 4s23d4
⎯ Occurs because the 4s & 3d orbitals are very close in energy
⎯ These anomalies occur in the f-block atoms f & d orbitals as well
⎯ Copper another anomaly
Chemical Bonds
⎯ Three basic types
Ionic: electrostatic attraction
Covalent: e- sharing
Metallic: metal atoms bonded to several others
Lewis Symbols
⎯ One dot for each valence e-
⎯ Octet rule (s + p = )
⎯ Duplet rule (max 2?)
Ionic Formation:
⎯ Metals lose e-, nonmetals gain e-
= 4 valence e-
Document Summary
Some irregularities occur when there are enough electrons to half fill s & d orbitals on a given row. (not universal for all anomalies) Occurs because the 4s & 3d orbitals are very close in energy. These anomalies occur in the f-block atoms f & d orbitals as well. Metallic: metal atoms bonded to several others. Octet rule (s + p = ) Several electrostatic interactions in these bond: attractions between nuclei, repulsions. Lone pairs: e- located only 1 atom on lewis structure. Pcl3: count n0 of valence e- for bonding. P: 5 valence e- x 1 atom = 5 e- Cl: 7 valence e- x 3 atoms = 21 e- Total: 26 e- for bonding: count each n0 e- if each ato(cid:373) is (cid:862)happy(cid:863) (cid:862)happy(cid:863): satisfy the octet or duplet rule. P: 8 x 1 atom = 8 e- Cl: 8 x 3 atoms = 24 e- Total : 32e- for happiness: count n0 of bonas.
