Chapter 5 - Electrons in the Atom What is an atom?

3 WORDS we use to describe where the electron might be… 1. Principle Energy Level – The energy level denoted by the principal quantum number (n) 2. Sublevel – characteristic shapes which can predict the location of the electron 3. Electron Orbitals (atomic orbitals) – Another name for sublevels – s p d & f

Principle Energy Levels of Electrons (n) n tells you how many sublevels can be found in that energy level Principle Energy Level Sublevels– orbitalsElectron capacity 11 s 2 22 s p = 8 33 s p d = s p d f = 32

Sub Levels / Electron Orbitals s-orbital (1 shape) spherical p-orbitals (3 shapes) pair of lobes d-orbitals (5 shapes) double dumbbells f-orbitals (7 shapes) fluctuating Orbital—A region of space in where there is a high probability of finding an electron **Each Orbital can hold 2 electrons

1.Aufbau Principle 2.Pauli Exclusion Principle 3.Hund’s Rule

The Aufbau Principle Aufbau Principle—An electron enters the orbital of lowest energy first Deals with the ground state (most stable state) of an atom Aufbau is German meaning "building up, construction”

The Electronic Configuration of Helium He: Atomic # of 2, 2 electrons in a neutral He atom H 1s 1  _ He 1s 2  1s1s Pauli Exclusion Principle: 1.Each orbital can only hold 2 electrons 2.If there are 2 electrons in the same orbital they must have the opposite spin.

Hund’s Rule AKA rule of maximum multiplicity Sublevels fill so that the number of unpaired electrons are maximized

Energy Level Sublevel # of electrons present H 1s  H 1s 1 Electronic configuration Orbital Energy Level Diagram Putting it together

Periodic Table – orbital organization

Electrons Changing Energy Levels Electron configurations show electrons in ground state Ground state –when an electron is in its lowest energy level the most stable state Excited state –when an electron is in a higher energy level than the ground state. How is light produced? –When an electron moves from a higher energy level to a lower energy level, it emits energy in the form of photons. Photons –light quanta or particles of light –Light has different colors depending on its energy.

What’s in a WAVE? Wavelength λ – Distance from consecutive corresponding points on a wave Frequency f – Measure of how many waves pass a given point per second Amplitude A – The height of the wave from the normal Relationships – Equations – The shorter the wavelength the higher the energy Speed of Light c – 3.0x10 8 m/s (299,792,458 m/s) Planks Constant h – 6.626x Js c = f λ

Light waves & Identifying elements Continuous spectrum – Produced from white light and contains all wavelengths of visible light Atomic Spectra Lines – Specific wavelengths of light seen through a spectrometer produced when a photon is emitted from a specific light source – Each element has a unique line spectra

Discharge Lamps