Korean, Edit

Chapter 1-1. Lewis Structures

Recommended reading: 【Organic Chemistry】 Chapter 1. Basics of Organic Chemistry

1. How to Draw Lewis Structures

2. Rules of Lewis Structures

3. Complicated Lewis Structures

1. How to Draw Lewis Structures

⑴ 1^st. After determining the order of arrangement of each atom, indicate the valence electrons of all atoms

Figure 1. Step 1 of Lewis Structures

In CNO^-, the excess electron can be assigned to any atom

⑵ 2^nd. Connect these atoms arbitrarily

Figure 2. Step 2 of Lewis Structures

⑶ 3^rd. Move electrons appropriately to satisfy the octet rule

Figure 3. Step 3 of Lewis Structures

① The movement of electrons does not need to be restricted by resonance rules

② Exceptions to the octet rule: Radicals can exist

③ For second-period atoms, the outermost electrons must never exceed eight

⑷ 4^th. If multiple structures are possible, consider formal charge

Figure 4. Step 4 of Lewis Structures

2. Rules of Lewis Structures: Note that these do not always apply

⑴ Except for diborane (diborane), H is always a terminal atom

Figure 5. Structure of diborane

⑵ Choose the central atom as the atom with the smallest ionization energy

⑶ Arrange atoms symmetrically around the central atom

① Example. SO₂ is arranged as OSO, not SOO

② Counterexample. N2O is arranged as N2O, not NON

⑷ For simple atoms, the central atom is written first

① Example. OF₂ is arranged as FOF, not OFF

② Counterexample. For acids; H2S is arranged as HSH, not HHS

⑸ In oxoacids, H is attached to O

① Example. H2SO4 = (HO)2SO2

3. Complicated Lewis Structures

⑴ CNO^-

Figure 6. Structure of fulminate

⑵ N₂O

Figure 7. Nitrous oxide

⑶ NO₂: Note that a structure with a radical on oxygen is possible

Figure 8. Nitrogen oxide

⑷ NO₂⁺

Figure 9. Nitronium ion

⑸ NO₂^-

Figure 10. Nitrogen oxide anion

⑹ NO₃

Figure 11. Nitrogen trioxide

⑼ NO₃^-: Structure of HNO₃ or HONO₂

Figure 12. Nitrate ion

⑽ O₃

Figure 13. Ozone

⑾ SO₂

① Application of the expanded octet rule

② The actual structure is sp2 hybridized with a formal charge of +2 on S

Figure 14. Sulfur dioxide

⑿ SO₃

① Application of the expanded octet rule

② The actual structure is sp² hybridized with a formal charge of +3 on S

Figure 15. Sulfur trioxide

⒀ SO₄^2-

Figure 16. Sulfate ion

Input: 2019.03.23 13:34