The Chemistry Book

From The Chemistry Book

Contents 1 Atoms 1.1 The Atomic Theory 1.1.1 Dalton's postulates 1.1.2 The Atomic Models 1.2 The Atomic Structure 1.2.1 Electrons 1.2.1.1 The Bohr Theory 1.2.1.2 Quantum Numbers 1.2.1.3 Shells, subshells, and orbitals 1.2.1.4 Aufbau Principle 1.2.1.5 Electronic structure and the periodic table 1.2.1.6 Writing electron configurations 1.2.2 Protons 1.2.3 Neutrons 1.3 The Nucleus 2 Elements 3 Periodic Table 3.1 Layout

Atoms

The Atomic Theory

Dalton's postulates

The Atomic Models

1803: John Dalton, atoms are tiny, indestructible partilces, with no internal structure
1897: J.J. Thomson: Discovers the electron and develops the plum-pudding model.
1904: Hantaro Nagaoka suggests atoms have nucleus
1911: Ernest Rutherford; Gold foil experiment leads to nuclear atom model
1913: Neils Bohr; electron moves in circular path around nucleus at fixed energy levels.
1923: Louis de Broglie; electrons have wave and particle properties.
1926: Erwin Schrodinger describes motion of electrons leading to electron cloud model
1932: James Chadwick confirms neutrons

The Atomic Structure

Electrons

Electron Configurations

The Bohr Theory

Quantum Numbers

Shells, subshells, and orbitals

Aufbau Principle

Order of increasing energy
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d

Electronic structure and the periodic table

Writing electron configurations

Protons

See definition of protons. The Atomic number of an element is equal to the number of protons.

Neutrons

Isotopes

The Nucleus

The majority of the atomic mass is located in the nucleus of the atom.

Elements

Periodic Table

Constructed in vertical columns called groups or families and rows called periods.

Layout

Three distinct areas of the periodic table.

1. Main group elements
2. Transition group elements
3. Inner transition group elements

• Classical - Main groups
• Amended - Main groups and transition groups labeled
• Modern - Arabic numerals 1 through 18