As the atoms of the elements from atomic number 2 to atomic number 9 are considered
in sequence from left to right on the Periodic
Table, the covalent atomic radius of each
successive atom is
and the
nuclear charge is

smaller, less
smaller, greater
larger, less
larger, greater

smaller, greater

Explanation:

Moving from left to right in the periodic table, we notice that the magnitude of nuclear charge increases with increasing atomic number.

Recall that across the period, nuclear charge increases without a corresponding increase in the number of shells hence the size of the atom (atomic radius) contracts due to a greater pull of the nuclear charge on the electrons.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.