Answer to Question #275480 in Inorganic Chemistry for Loco Kilo

Question

1.    How do the sizes of atoms change as we move?

a. From left to right in a row in the periodic table?

b. From top to bottom in a group in the periodic table?

c. Arrange the following atoms in order of increasing atomic radius: F, P, S, As

d. Arrange the following atoms in order of increasing atomic radius: Al, Nb, Se, F, Mn 

Answer 1

On the periodic table, atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you move down a group (due to the increasing number of electron shells).

As of now, the order of increasing atomic radius is P, S, and then As in that order. Fluorine F is in period 2 i.e. it has only 2 electron shells. That makes the element the smallest in the list.