video tutorial ChemPlayer tutorials - electrons part 1

Electrons and atomic structure — summary

The content explains that chemistry arises from electrons around a nucleus; the nucleus remains unchanged in chemical reactions, while electrons determine chemical behavior. Electrons are extremely light and exhibit quantum behavior, so they are better thought of as waves around the nucleus, forming standing wave patterns called orbitals in three dimensions. These orbitals come in harmonics with nodes, and electrons occupy them in specific energy-dependent sequences. Each orbital can hold two electrons with opposite spins. The combination of orbitals forms shells, and full shells are stable. The outer, partially filled orbitals primarily determine an atom’s chemistry. Atoms tend to lose or gain electrons to achieve a full, stable shell. Sodium tends to lose its outer electron, forming a stable configuration and a Na+ ion; oxygen tends to gain electrons to complete its shell, forming an oxide ion (O2−). The interaction of sodium and oxygen is a redox process: oxidation (loss of electrons) and reduction (gain of electrons) must occur together. The example Na and O leads to sodium oxide (Na2O) as a product. The next tutorial will cover how electrons form bonds and molecules. A set of key points and a glossary are provided for further study.

Key points

1. Electrons are three-dimensional waves around the nucleus of an atom, forming harmonics and shapes called orbitals.
2. Each orbital can hold up to two electrons.
3. Orbitals fill in an energy-based sequence.
4. Orbitals combine to form shells; full shells are very stable.
5. The outer, partially filled orbitals determine chemical behavior.
6. Atoms seek to lose or gain electrons to achieve a stable full shell.
7. Loss of electrons is oxidation.
8. Gain of electrons is reduction.

Glossary

• Orbitals: three-dimensional regions around the nucleus where electrons are likely to be found; come in s, p, d types and can contain two electrons each.
• Shells: sets of orbitals at a given energy level; full shells are stable.
• Oxidation: loss of electrons.
• Reduction: gain of electrons.
• Ion: atom with a net electric charge due to loss or gain of electrons.
• Oxide ion: O2− ion formed when oxygen gains two electrons.