Khan Academy

More on orbitals and electron configuration (K-A)

The periodic table, electron shells, and orbitals (K-A)

Orbitals (K-A)

Valence electrons and bonding (K-A)

Valence electrons and ionic compounds

Atomic number, atomic mass, and isotopes (K-A)

Elements and atoms-video (K-A)

Matter, elements, and atoms (K-A)

Introduction to the atom (K-A)

Carbon as a building block of life (K-A)

Carbon and hydrocarbons (K-A)

Elemental building blocks of biological molecules (K-A)

Elements and atoms (K-A)

Functional groups (K-A)

Matter, elements, and atoms (K-A)

Functional groups (video) (K-A)

Dehydration synthesis or a condensation reaction (K-A)

Chemical bonds (K-A)

Hydrolysis (K-A)

Introduction to macromolecules (K-A)

Ionic, covalent, and metallic bonds (K-A)

Antiparallel structure of DNA strands -video (K-A)

DNA-video (K-A)

Molecular structure of DNA-video (K-A)

Nucleic acids-link (K-A)