About carbon

  • Foundation of biology.

  • 6 proton + 6 neutron + 6 electron

  • Two electron shells: 2 electrons locate on the first shell and 4 locate on the outer shell.

  • Lewis dot structure

Gilbert Lewis

The scientist behind these famous terms:

  • Lewis dot structure
  • Valency theory
  • Lewis acids and bases

Some facts about him: He was nominated 35 times for Nobel’s Prize but ended up with zero prize. What a great man!

Octet Rule

Each atom needs 8 electrons in the outer shell … to be fulfilled and happy.

This is a rule of thumb for a “happy relationship” among atoms to form a long-lasting family (molecule).

Types of bonding

Covalent bonds

When atoms share electrons with each other. Ex: $CH_{4}$, $O_{2}$, $NH_{4}$

  • Non-polar covalent bond. Ex: $O_{2}$
  • Polar covalent bond: there exists negative and positive pole. Ex: $NH_{4}$

Amino acids are formed by covalent bonds.

Ionic bonds

  • do not share electrons
  • donate or accept electrons
  • live as a charged atom or ion

Alkali metals + Halogens

Examples: $NaCl$, $KF$, etc.

Hydrogen bonds