Answer to Question #188887 in Chemistry for Anisa Tamaivena

Question

Using the periodic table, rank the elements in the following set in order of increasing (from lowest to highest) first ionization (IE1); F, Rb, Be, N. Explain your answer.

Answer 1

Solution:

F - fluorine,

Rb - rubidium,

Be - beryllium,

N - nitrogen.

The first ionization energy (IE1) decreases from top to bottom in groups, and increases from left to right across a period. 

• From top to bottom in a group, orbitals corresponding to higher values of the principal quantum number (n) are being added, which are on average further away from the nucleus. Since the outermost electrons are further away, they are less strongly attracted by the nucleus, and are easier to remove, corresponding to a lower value for the first ionization energy.
• From left to right across a period, more protons are being added to the nucleus, but the number of electrons in the inner, lower-energy shells remains the same. The valence electrons are therefore held more tightly, the atom decreases in size, and it becomes increasingly difficult to remove them, corresponding to a higher value for the first ionization energy.

(https://www.angelo.edu/faculty/kboudrea/periodic/trends_ionization_energy.htm)

Thus, fluorine (F) has the highest first ionization energy of the presented set of elements, and rubidium (Rb) has the lowest.

(the lowest) Rb < Be < N < F (the highest)

Answer: Rb < Be < N < F