CHM136H1 Chapter Notes - Chapter 1: Antibonding Molecular Orbital, Methyl Group, Headon

• School: UTSG
• Department: Chemistry
• Course: CHM136H1
• Professor: Thavarajah/ Woolley/ Nitz

Document Summary

The atomic number (z) is the number of protons in the atom"s nucleus. The mass number (a) is the number of protons plus neutrons. All the atoms of a given element have the same atomic number. Isotopes atoms of the same element that have different numbers of neutrons and therefore different mass numbers. The atomic mass (atomic weight) of an element is the weighted average mass in atomic mass units (amu) of an elements naturally occurring isotopes. Quantum mechanics: describes electron energies and locations by a wave equation: tries to describe the position of electrons in atoms, shows most probable area of electrons in atoms. Four different kinds of orbitals for electrons based on those derived for a hydrogen atom. S and p orbitals most important in organic and biological chemistry. D orbitals elongated dumbbell-shaped, nucleus at center. Orbitals are grouped in shells of increasing size and energy. Different shells contain different numbers and kinds of orbitals.