Lab 7.3 Reactivity of Metals

1.  Answer the lab question on the first page of this lab.  CITE EVIDENCE FROM YOUR OBSERVATIONS! Make sure you explain thoroughly.

2.   Why do elements in the same column on the Periodic Table tend to have VERY SIMILAR properties?  Explain in terms of electron configuration! Use specific examples from your groupings.

3.   Describe what happens when an atom of sodium atom interacts with an atom of a nonmetal.  In your description, indicate:

a.   Whether the sodium atom loses or gains electrons,

b.   Whether the sodium atom becomes a positive or negative ion,

c.   The electrical charge of the sodium ion,

d.   Which noble gas sodium’s electron configuration becomes like,

e.   Whether the sodium atom becomes more or less stable as a result of reacting.

ENRICHMENT: 

The elements Li, Na and K are too reactive to be found in nature as pure elements.  Research how chemists obtain pure sodium in the form like we used in lab.

Lab 7.2 Periodic Trends Activity

These three trends are more challenging to explain, explain them:

·        Atomic radii trend going from left to right across a period.  The heaviest elements in a period have the smallest radii. WHY?

              ·        Electronegativity decreases when you move down a group. The larger the atom in the same group, the less it attracts electrons. WHY?

·        Ionization energies as you go from left to right across a period.  It kind of makes sense that it is harder to strip an electron from a metal than from a non-metal, but WHY is this so?

The key to explaining these trends is to figure out what “nuclear charge” is, and then to figure out what it has to do with these property trends.  Google will be a big help if you ask the right question in the search bar!  Good luck, and of course, talk with your teacher as needed!



Why do you think the trends are referred to as being "PERIODIC." Hint the word periodical is sometimes used with magazines and newspapers that are delivered at regular intervals.

Blog 7.1 Flame Tests and Emission Spectra

Conclusion:

1.  After seeing the spectra of various elements in this lab, why do you think an element’s spectrum is often called its “fingerprint?”   Explain using the terms ground state, excited state, and electron configuration.

2. Explain how a spectra is formed. Make sure to include the process and the steps that occur. This is important that you can describe what happens during the changes between ground and excited state, and how energy is released and absorbed.

ENRICHMENT:

1.  Research the discovery of the element Helium, and why it is given the name it has.

2.  Find out how astronomers use what is called a “red shift” or a “blue shift” to know whether a galaxy is moving towards or away from our galaxy.  To do this:

a)  Explain what blue shifts and red shifts are, and what they have to do with an element’s spectrum.

b)  Explain how the ratio of blue shift to red shift galaxies is used as evidence that the universe is expanding.

c)  Find out what Sir Edwin Hubble had to do with all this.