10 9 8 7 6 5 4 3 2 1 10/28 Flame Tests Make a 2 column by 6 row table in your notebook Label the Columns “Compound” and “Observations” Light your bunsen burner Dip the wooden splint in the liquid Heat it in the flame Record observations for all 5 compounds Na, Li, K, Sr, Cu WRITE A HYPOTHESIS OR EXPLANATION. Why do you think what you are observing is happening?

Electromagnetic Spectrum Long wavelength Low energy Low frequency Short wavelength High energy High frequency

Bohr’s Model of the Atom nucleus contains positive protons and neutral (no charge) neutrons e- circle the nucleus in orbits, like planets around the sun energy levels are quantized meaning only certain orbits are allowed, the e- can’t be between every atom has it’s own unique set of energy levels Bohr Model

The Quantum Model Quantum Model electrons in orbitals = 3D volume of space where electrons are most likely to be found electron “cloud” represents a 95% probability that the e- will be inside Quantum Model e- are thought of as both waves and particles (weird right? That’s called wave-particle duality) which means you can not know the exact position or speed of an e- (that’s called Heisenberg’s Uncertainty Principle)

Orbitals

Orbitals

Spectroscopy Lab Background Background: The normal electron configuration or arrangement of atoms is known as the ___________ ________. This is the most _________ energy state and all e- are in the __________energy levels possible. When electrons absorb enough energy they can “jump” to higher energy levels and are said to be in the _________ ________. However, the excited state is _______________ and as electrons “relax” back down to lower energy levels the extra energy is ___________ or given back off as ____________ light. ground state stable lowest excited state unstable emitted visible

Let’s look at the Hydrogen emission spectrum! Spectroscopy Lab Background Each element, depending on its own unique _______________ _________________ (or arrangement), will emit a different _________________ of colored light that our eyes interpret as a ___________ color. In order to actually see the individual colors we need to use a ____________________, which has a _________ that separates the different wavelengths of light. Let’s look at the Hydrogen emission spectrum! electron configuration combination single spectroscope prism

Emission Spectrum of Hydrogen

Spectroscopy Lab Background If we look at the _______________ _____________ of a single element we will see only certain unique bright lines. Looking at this pattern of colored lines is one of many similar analytical techniques chemists use to identify substances called ________________. Each colored line in an emission spectrum represents a specific or ________________ electron transition. electron transition corresponding to a particular energy difference. emission spectrum spectroscopy quantized

Only certain colors are emitted because the transitions are quantized Electronic Transitions Heat, electricity, or light provides energy to excite e- UV, Visible Light, or Infrared emitted as e- drops back to lower energy levels photon Unstable excited e- 25 24 23 e- e- e- n = 5 n = 4 e- e- n = 3 e- n = 2 Only certain colors are emitted because the transitions are quantized p+ n = 1

Spectroscopy Lab Background If energy levels were not quantized, then theoretically electrons could make ______ transition. This would result in a full spectrum of visible color in the emission spectrum or in other words we would see __________ light emitted by any excited atom as it relaxes back to the ground state. However, experiments show that only certain colors are emitted. This is direct evidence that ______________ ____________ _________ exist and confirmed __________ model of the atom which has electrons in quantized _____________ around the nucleus. any white quantized energy levels Bohr’s orbit

ESCHS RECYCLES IN THE CLASSROOM EACH CLASSROOM SHOULD HAVE 3 BINS WITH SIGNS! WE DEPEND ON YOU TO SORT YOUR RECYCLING

ESCHS RECYCLES AND COMPOSTSIN THE CAFETERIA Metal, Glass, Plastic, Cartons Landfill Styrofoam, Plastic bags, Wrappers Food Scraps & Paper Milk & Juice container

e- e- e- e- n= 1 n=2 n=3 n=4 n= 1 n=2 n=3 n=4 Long wavelength Low energy Low frequency Short wavelength High energy High frequency e- e- e- e- n= 1 n=2 n=3 n=4 n= 1 n=2 n=3 n=4

Absorption vs. Emission Spectra

Absorption vs. Emission Spectra

Absorption vs. Emission Spectra

Stellar Spectra

Stellar Spectra – Which elements?

700 650 600 550 500 450 400 H 700 650 600 550 500 450 400 He 700 650 600 550 500 450 400 Ne 700 650 600 550 500 450 400 Hg 700 650 600 550 500 450 400 Solar

Make three columns in your notebook 10 9 8 7 6 5 4 3 2 1 10/31 Spectroscopy Lab Data Make three columns in your notebook Mercury Hg Helium He Neon Ne

accurate / inaccurate / fairly / somewhat / partially / mostly Science Writing Style: Spectroscopy matched … the red line at 650 nm observed … the green line (486 nm) … the 410 nm line (purple) in a band from ___ to ___ … the 580 nm yellow line in a pair / group / set of lines shifted near accurate / inaccurate / fairly / somewhat / partially / mostly

accurate / inaccurate / fairly / somewhat / partially / mostly Science Writing Style: Openers The experimental results for the Helium emission spectrum were ________ compared to the accepted spectrum because …. Compared to the known spectrum, the experimental results for the Helium emission lines were _________ because… The experimental Helium spectrum results were ________ in comparison to the accepted emission values because… accurate / inaccurate / fairly / somewhat / partially / mostly matched shifted … the red line at 650 nm observed near … the green line (486 nm) … the 410 nm line (purple) in a band from ___ to ___ … the 580 nm yellow line in a pair / group / set of lines