The inner planets are called terrestrial because they
a.
have no atmosphere.
c.
have earth-like oceans.
b.
are small and highly dense.
d.
are visible from earth.

The correct answer is D

It’s c it stays the same. and the atomic number goes up by 1. a neutron has changed into a proton plus an electron. the electron is emitted as a beta particle.

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts