(b) what determines the order of the elements in a period?

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

How have the greenhouse gasses increased from the year 2000 to 2018

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?