Who was one of the first scientists to realize the effects of CO2 in the atmosphere? When did he do this?

How was it measured?

Where?

Who: Svante Arrhenius.

When: Claimed in 1896 that fossil fuels has a negative effect on our atmosphere.

How: Svante Arrhenius proved that fossil fuels had a negative effect by calculating the output of buildings that emit fossil fuels, and lead to the conclusion by his calculations that the industry might one day bring global warming.

Where:

I cannot find any source that mentions the where. What do you mean by where?

I hope my other information help you. I apologies to only be able to answer partially.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.