Part One Quantum Numbers

Terms to Know Energy level/shell: describes an area that is a specific distance from the nucleus Subshell: uniquely shaped regions at each energy level where a specific number of electrons may be found Orbit: an area within a subshell which can hold only 2 electrons

Energy Level Subshell Orbit Shell Distance from nucleus Specific shaped region within a shell Orbit Area within subshell which only holds 2 electrons

Defined Quantum numbers describe electrons. You can think of an electron’s quantum numbers as being that electron’s address.

Our numbers To describe the exact location of an electron we need 4 numbers: Principle Angular momentum Magnetic Spin

Principle Represented by n Tells us how far away the electron is from the nucleus

How to find principle numbers Most elements have multiple energy levels, so they have multiple principle numbers. Period = number of energy levels Transition metals & inner transition metals are exceptions.

Atom = Upside down pyramid

Angular Momentum Represented by l Describes the shape of the subshell where the electron can be found Energy levels can have multiple subshells

Angular Momentum We use letters to represent the angular momentum shape:

Electrons per subshell S subshells hold up to 2 electrons P subshells hold up to 6 electrons D subshells hold up to 10 electrons F subshells hold up to 14 electrons If each subshell contains orbits, and each orbit can hold 2 electrons, how many orbits are within each subshell?

Remember! Hydrogen and Helium only have one energy level, but all other elements have multiple levels. Energy levels are cumulative. Subshell shapes are also cumulative.