1. Based on the periodic trends for metallic properties, which
elements have the biggest atomic
radius?
2. Sort the elements in order of
increasing metallic properties. Ca,
M.Sc, Be, Bd
3. Why is the electronegativity
value of most noble gases zero?
4. A nonmetal has a smaller ionic
radius compared with a metal of
the same period. Do you agree?​

1) The largest atomic radius has element 1) tin 2) carbon 3) Germanium 4) silicon. 

2) Be, Mg Ca, Sc,???

3) All their energy levels are filled to the end, so they do not act as oxidizers and restorers, although they are non-metallic.

4) I agree, that atomic radii, when moved from left to right in the same period, decrease. This is because electrons are more attracted to the nucleus as the core charge increases. Even an increase in the number of electrons on the outer shell (e.g. fluoride compared to oxygen) does not increase the size of the atom. That is, the fluoride atom is smaller than the oxygen atom.