periodic trends for chem??

Question

which is larger in atomic radius? Nitrogen or Boron and why?
which is larger in ionic radius? Rb+ or Br- and why?
which is larger in electronegativity? Oxygen or Sulfur and why?

i dont get trends at all :[
help
thanks!

Answer 1

Atomic Radius decreases as you go from left to right across a period and increases going down a group. Since Boron and Nitrogen are in the same period, the larger one would be farther to the left. Boron is to the left of Nitrogen; Boron is bigger.

Rb+ and Br- have the same number of electrons (36 by number), so the difference in size will depend on how many protons are pulling on those electrons (Opposites attract). Since Bromine has fewer protons in its nucleus than Rubidium, Br- would be larger.

Electronegativity tends to increase going from left to right across the periods and decreases going down the groups. Oxygen and Sulfur are in the same group. Oxygen is above Sulfur. Oxygen has a higher electronegativity.