Question

Of the following, which gives the correct order for atomic radius for mg, na, p, si and ar?

a. Mg > Na > P > Si > Ar
b. Ar > Si > P > Na > Mg
c. Na > Mg > Si > P > Ar
d. Si > P > Ar > Na > Mg
e. Ar > P > Si > Mg > Na

Answer 1

The correct order for atomic radius is:

d. Si > P > Ar > Na > Mg

The size of an atom increases as you go down a column in the periodic table, because each electron is added to a higher energy level farther away from the nucleus. The size of an atom decreases as you go across a row in the periodic table, because the effective nuclear charge increases, pulling the electrons closer to the nucleus.