What organ helps child develop immunity

This is a characteristic of the elements in the periodic table that shows a pattern. it may increase or decrease across or down the table.

How many miles of water are produced if 5.43 mol pbo2 are consumed

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.