What is a displacement reaction

Apeak with a retention time of 407 s has a width at half-height (w1/2) of 7.6 s. a neighboring peak is eluted 17 s later with a w1/2 of 9.4 s. a compound that is known not to be retained was eluted in 2.5 s. the peaks are not baseline resolved. how many theoretical plates would be needed to achieve a resolution of 1.5?

As you move from right to left on the periodic table the atomic radius fill in the blank

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.