If you mix chlorine lithium and nickel together which two elements would be the most reactive?

Helium will be inert. Lithium is the most reactive element, followed by chlorine.

Explanation:

The elements tend to resemble the closest noble gases in terms of their electronic configuration of the last layer, that is, having eight electrons in the last layer to be stable. Then, the reactivity of an element measures the tendency to combine with others to generate the mentioned stability.

Within a period, the groups located on the left of the periodic table are more reactive than groups on the right. This is because it is easier to lose the electron of the last layer possessed by the elements located on the left than more than one electron in the rest of the elements. When we reach a certain group the trend is reversed since it will be easier to gain the missing electrons to resemble the nearest noble gas. Therefore, in a period the reactivity of metals increases the further to the left in the period (less electrons to remove). The reactivity of nonmetals increases as the period progresses since it is the case in which it is easier to acquire electrons to acquire stability, and increases to advance in a period since the less electrons they need to acquire, the more reactants they are.

Within a group, as we descend into it, the electrons of the last layer are farther from the nucleus and, therefore, it will be easier to remove them. In the case of nonmetals, it will be more difficult to take electrons. Then the reactivity of the metals increases when advancing in a group (greater tendency to lose electrons) and the reactivity of the nonmetals increases the higher in the group (greater tendency to take electrons).

Finally, you have noble or inert gases. Its inert name is due to the lack of reactivity with other elements. This is due to its electronic configuration, because its outermost layer or valence layer is always complete, without the need to share, transfer or receive electrons forming bonds. That is, its outer layer is so stable that the element tends not to react with others except in very specific cases.

Taking into account everything mentioned above, it is possible to say that helium is a noble gas, so it will be inert. Lithium is the most reactive element, followed by chlorine.

quartz

explanation:

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.