Chemistry/Mendeleev Marking Scheme
Maximum = 5 (Table) + 7 (Questions) = 12
ANSWERS TO TABLE:
1 = (blank) 4 = F 7 = G 10 = A 2 = B 5 = I 8 = E 11 = (blank) 3 = H 6 = D 9 = J 12 = C
1. How were elements in Medeleev’s periodic table arranged?
(1) Mendeleev arranged the elements according to their atomic masses (and in horizontal rows called periods and vertical columns called families)
2. What is Medeleev’s periodic law?
(1) If elements are arranged according to their atomic mass, a pattern can be seen in which similar properties occur regularly.
3. Why was Mendeleev able to predict the properties of elements which had not yet been discovered?
(1) He was able to predict the properties from the pattern of properties of elements in the same family and period.
4. Do all the properties follow a smooth trend when comparing the elements or compounds in a family? Support your answer using data from your finished chart. (1) The properties follow a general trend but not a smooth trend. For example, the densities in column 2 and column 1 and the melting points in column 11 have irregularities.
5. You have been called in as a highly paid consultant to the Atomic Energy Commision to predict the properties of Element 114. Although this element has not been discovered, nuclear physicists are sure that they can make it some day soon. Your task is to predict as many as you can of the properties of Element 114, which will lie directly underneath the element lead (Pb) on the periodic table. They are paying you for every property you predict, so if not sure, make a good guess.
- physical state = solid
- density (g/mL) > 11.4
- hardness = soft to very soft
- conductivity = good to very good
- melting point = hard to predict (may say >327 or <327)
- solubility in water = none
- colour = some description with “grey” in it