Chemistry Midterm Review

Matter: Particulate (chunk-like) and moves in definite paths.

Energy: Continuous (wave-like) and moves in all directions.

• 1. Greater nuclear charge, lower (stabalize) orbital energy.
• 2. Electron-electron repulsions, raise (destabalize) orbital energy.
• 3. Electrons in outer orbitals (higher n) are shielded from the full nuclear charge, so they have higher energy.
• 4. Orbitals with good penetration (having electron density close to nucleus), have lower energy.

The nuclear charge an electron actually experiences as a result of shielding effects due to the presence of other electrons.

Shielding = lower Z_eff = charge makes electron easier to remove.

• Zeff Constant
• Radius Increases
• EA Less Negative
• EN Decreases
• IE Decreases

• Zeff Increases
• Radius Decreases
• IE Increases
• EA More Negative
• EN Increases

• Loses electron
• Is oxidized
• Oxidation # Increases

• Gains electron
• reduced
• Oxidation # Decreases

*Halogens are easily reduced.

• RA:
• -easily loses electron (low IE)
• -Is in unusually low oxidation states

• OA:
• -easily gains electron (highly -ve EA)
• -is in unusually high oxidation states

• -Colourless gas, low mp, low bp
• -Most abundant element in universe (Stars)
• -Normally a nonmental
• -Preperation:
• 1.Most abundant source on earth is H20
• 2.Extraction of the element by reduction of H2O. Electrolysis is NOT a practical method.
• -Uses: 1. Production of Ammonia
• 2. In petroleum refining, converting oils to fats.
• Disadvantages: no cheap source and transport and storage are challenging.