Monday,+May+16th

Waves and Quantum Mechanical Model Webquest
__**Intro**__: The essence of Quantum Mechanics and Relativity Theory states that all things are actually waves...even particles like protons, electrons, atoms, baseballs, satellites all have wave functions. So to better understand this mysterious concept, let's use this online webquest to help.

Waves can be described by their speed, wavelength and frequency. All electromagnetic waves move at the same speed, the "speed of light" which 186,000 miles/sec. Wavelength is the distance between crests in a wave. Frequency is the number of cycles that happen per unit of time.

Write answers on a sheet of lined paper. Every individual is responsible for keeping his/her own recorded answers.

Site #1 [|Vibrating Charges and Electromagnetic Waves - Radiation] Typically when something "shakes" it makes a wave. Use your mouse to drag the negative charge up or down by different amounts, then let it go to start oscillating. Now move the slider to adjust the tension which makes for quicker repeats of a cycle, this means a higher frequency. Read the discussion below the animation and then the following question.

Q1) What happens to the wavelength as the frequency increase (having more cycles per sec)? Q2) What happens to the wavelength as the frequency decreases?

Site #2 [|Electromagnetic Spectrum] Q3) List the common names of electromagnetic radiation in order of longest to shortest WAVELENGTH. Q4) Which type of electromagnetic wave has a wavelength that is about 10m to 1000m long? Q5) What are the two types of waves that have the highest energy per photon? Do you think this has a correlation to possible cell damage to humans? Explain why or why not. Q6) What is the relationship between frequencies and energy content of the waves? Q7) Which waves are the human eyes able to detect or see? In your opinion, is this a large or small part of the entire possibility photon types (the electromagnetic spectrum)?

Back to Site #1, but a different section [|Spectral Lines] Read this entire page. Q8) Physicists know that heating things cause the atoms to "wiggle". What is ejected from atoms when they wiggle? Q9) Use the spectral line changer to view the visible spectral lines of at least 4 or 5 elements. Now describe what spectral lines in your own words. And why is it they could be described as "signatures" or "fingerprints" of elements.

Click on the **next button** at the bottom of the the Spectral Line page, which will connect to **Energy Levels**. Q10) Describe what is required for an electron to jump to a higher energy level. Q11) Describe what happens when an electron returns to its lower energy level.

Click on the **next button** of the bottom of the Energy Levels page, which will connect to **Atomic Spectra**. Atomic Spectra are the "signature" spectral lines released by specific atoms. Specific wavelengths are released by each atom because only specific "jump" between that atom's energy levels can occur. Experiment with jumping the electron in the Hydrogen atom to outer and inner orbits to see what happens with the photons absorbed or released. Q12) If you make the electron jump downward, then return it to the outer ring what do you notice about the photon released or absorbed? Q13) Start with the electron being highly energized in the outermost shell. Now click to allow it to drop to each of the lower energy level one at a time. What happens....why are three new spectral lines formed on the chart?

Click on **Making X-rays** at the bottom of the **Atomic Spectra** page. Q14) Use this page and your own intuition of what was just learned to explain how we make X-rays ( a very high energy photon of light)emit from Tungsten (a large atom with very high energy level orbitals).

Site #3 [|David Whizzy's Periodic Table] This interactive periodic table shows the first 4 periods (rows) of the periodic table. Notice that the atomic emission spectrum of each element is also shown for each element as you click on them in the table. The Bohr-type model on the left will also change with the pink dots representing electrons in the 1st energy level, the yellow dots representing the 2nd energy level, green dots the 3rd, etc. We will ignore the right side showing the ionization energy for now, but basically this will show that it always requires the least amount of energy (around 10 eV, electronvolts) to remove which ever is the outermost electron. Click on 5 to 10 different elements to get an idea of what changes each time, just explore.

Q15) Now click on Li, lithium. Click on the "nucleus view" and describe what you think is represented there? Q16) Now click on the "shell view" for lithium and describe what you see in the left diagram. Be specific about what the pink and yellow dots represent. Q17) Normal lithium has an atomic # of 3 and a mass # of 7 amu. Do the diagram views agree with this? Explain. Q18) Notice the atomic emission spectrum for Li, what color spectral lines does Li emit? Q19) In order, click on the following elements: H, He, Li, Be, C, N, O, Cl, Ne, then Na, Mg. Describe what happens every time you proceed down the horizontal row or period. What happens when you jump down to the next row? Check out a few more and see if your patterns continues.

Q20) In order click H, Li, Na, K. Count the number of electrons in each energy level as you go down this family or group. Remember that the 1st (inner) to 4th (outer) energy levels the colors from pink to yellow to green to aquamarine. What is similar about the number of valence electrons in each and what is different about which energy level the valence e- is/are found in? Hint: you can summarize the number of electrons in Na saying there are 2-8-1 in the 1st-2nd-3rd energy levels respectively.

Q21) In order click on He, Ne, Ar, Kr. What is similar about the number of valence electrons in each and what is different about which energy level the valence e- is/are found in?

Q22) Notice that the sublevels of the electrons are listed on the right as s, p and d. You will learn later what these mean, but for now within each Energy Level these are 3 of the possible patterns or sublevels that electrons can be in. Click on the largest atom shown, Ar, which has all of its Energy Levels and sublevels maxed out. Count and list the maximum number of electrons found with each of these 3 sublevels: s, p and d. Now check around on other elements on the chart to make sure that none have more than this in any of their sublevels.

Q23) PREDICT before looking...what will be the similarities and differences in electron locations as you click on F, Cl, Br? Now do it and see if your prediction is right. Q24) Click on He-Li then Ne-Na and then Ar-K. Describe the general trend of what happens to the next electron added after each Noble gas.

Q25) What is special about He, Ne and Ar in regards to the "octet rule" of bonding (and electron transfer)? These elements have been referred to as "inert" which means unreactive. This means they do not accept or give away electrons. Explain why this would happen. Q26) Li, Na and K are likely to lose an electron. Why is this the case based on the octet rule? What electron would they lose (be specific)? Li? Na? K? After losing the electron, what elements would their energy levels be identical to?

Q27) O, S, and Se are likely to gain two electrons. Why is this the case based upon the octet rule? Where would the two new electrons go (be specific)? After gaining two electrons, what elements would their energy levels by identical to? )? S? Se? Q28) Based on the examples you just did try to PREDICT before looking ....how many electrons would by lost or gained by Mg and by F. And what elements would their energy levels be identical to for each after losing or gaining electron(s)? Now check to see if you were correct.

__**Summary**__ of what was learned in this webquest. Please use complete sentences. Q29) Describe some reasons why our current understanding of the atom is known as the Quantum Model. Q30) Is there a systematic way in which the periodic table is organize that helps us to make good predictions about what the electron configurations (the location of electrons) in atoms look like?

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