Can anyone help me? Plsss

According to periodic trend, which of the following most likely has the highest ionization energy? kr be ni sc

Ineed this asap part i: scientific method what is the difference between science and pseudoscience? what is the scientific method?

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?