eldon Unit 2: The periodic table Lesson 2: The periodic table and the atomic structure Apply 1. Classify the following elements as representative elements, transition metals or internal transition metals: a. sodium b. uranium C. chlorine d. gold e. gadolinium 2. Identify the period and the group or family to which the following elements belong: a. magnesium b. tin sodium period period period C. d. radon period uranium period e. 3. Which of the atoms in the following pairs of atoms will have the highest first ionization energy? to. Al, B b. Li, K C. B, TI d. F, N e. Ag, Rb 4. Predict the oxidation numbers for the following elements: a. calcium b. bromine c. aluminum d. nitrogen e. oxygen 5. Which element has the smallest atomic radius, strontium (Sr), silver (Ag), or rubidium (Rb)? 5. Order the elements I, Sn, Rb, Ag, and Zr in decreasing electronegativity.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

it's filtration, but this is an assumption so my apologies if i got this

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2