Periodic Chart, Part I

Particle	protons	electrons	neutrons
in A-E	1	1	0, 1, average = 0.000115
in A	2	2	1, 2, average = 1.99999866
in C	6	6	6, 7, 8, average = 6.0107
in C	7	7	7, 8, average = 7.00364
in B, C, E	8	8	8, 9, 10, average = 8.00448
in B, E	11	10	12, average = 12
in D	17	17	18, 20, average = 18.4848
in B, E	17	18	18, 20, average = 18.4848
in C	18	18	18, 20, 22, average = 21.985276

Questions

1. How many elements are present in substances in group C? [H, C, N, O, Ar][recall that the substances nitrogen, oxygen, argon, carbon dioxide and water were described in Classroom Activity 1]
2. Using the table above and your results from Classroom Activity 1, locate all the elements on the Periodic Chart that are present in the substances in group C.
3. How are the elements on the Periodic Chart ordered? What is the meaning of the integer that appears with each element?
4. Are all the members of an element the same? Explain. If they're not all the same, how can you know what element an atom is? [the number of protons]
5. Samples of matter are often analyzed by mass, because it is a very quick and accurate way of determining the elements present. [given proton and neutron masses], what would the mass of a chlorine-35 atom be? What about chlorine-37? What would the average be, based on distribution of atoms in naturally occurring chlorine?
6. [now that you know the # protons corresponds to the integer (atomic number), identify the other items on the table above
7. Supply formulas and propose names for the substances in A, B, D and E
8. the charged particles are called ions [what makes an ion? -- different number of electrons than protons]
9. How would you make a Br- ion?
10. What would S^2- mean and how would you make it?
11. For most of the particles above, more than one kind is possible, depending on the number of neutrons -- what would ¹³C mean in this context? How 'bout uranium 238?
12. Besides the integer, each element has another number (usually a non-integer). What is its significance?

Stability

Model: Atoms/Ions or Molecules?

Questions (continued)

1. Of the four [particles] above are stable as atoms/ions, which are most alike? Explain [could choose He and Ar for neutrality, or Na+ and Cl- for ions, but I will steer them toward Cl- and Ar, for isoelectronic]
2. [if gaining an electron has made a chlorine atom stable (as chloride) like an argon atom, then does it stand to reason that losing an electron makes a sodium atom stable?]
3. What is the name of the element that appears in the vertical group between He and Ar -- which in the table above is most like it? Explain [Na+]

Additional Practical Atmospheric Matters

(If you live on Venus or want to know the direction Earth is heading)

Questions (continued)

1. Identify as many of the substances as possible with your knowledge of substances above [SO2 and H2SO4 won't be identifiable with prior knowledge]
2. What is the primary constituent of the Venusian atmosphere? [Venus is a runaway greenhouse planet with evidence of past water -- it is hotter than Mercury, even though it is further from the Sun]
3. It is likely you were unable to identify all the substances in the Venus atmosphere based on your earlier knowledge. What is preventing you? [don't know what that yellow element is, even though the substances have oxygen and hydrogen]
4. So, what do you want to know about that yellow element in order to identify it? [protons, of course...]

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Activities