What is the trend of polarizability as a consequence of changing atomic radius from atom to atom?
An atom's polarizability is the ease to which the electron density in the atom can be distorted by another atom whose electron cloud approaches it.
Since the pull of the nucleus is weakest on the valence electrons, the outer region of the electron cloud tends to get distorted more easily when the atom is bigger because the valence electrons are on average farther away from the nucleus.
Therefore, polarizability increases with increasing atomic radius.
CHALLENGE: What happens to the polarizing ability of the atom as its atomic radius increases?