posted by Anonymous .
which of these elements-Na, Si, Cl, or Cs- has:
a)the highest first ionization energy?
b)the smallest radius?
c)the most metallic character?
I would go with Cl for a and b.
Cs for c.
how do you know?
a. radius generally decreases [within the same period(row)] from left to right because electrons are being added to the same shell but the nuclear charge is increasing. All except Cs are in the same period
b. smaller radius and higher nuclear charge means harder to pull the outside electron away (first ionization potential).
c. The most electropositive element in the table is in the lower left corner; the most electronegative element is at the top right (don't count the noble gases). .