Write the equation for the first ionization energy of silver. Include all states and charges. Include the energy term as IEi The first ionization energy of silver is 731 kJmol: Compare this to rubidium’= ionization energy in the textbook or online. Would you have predicted this relationship using periodic trends? Why or why not
The Correct Answer and Explanation is:
Equation for the First Ionization Energy of Silver:
Ag(s) → Ag⁺(g) + e⁻ IE₁ = 731 kJ/mol
Comparison and Explanation
The first ionization energy (IE₁) is the energy required to remove the outermost electron from a neutral atom in its gaseous state. For silver (Ag), the equation representing this process is:
Ag(s) → Ag⁺(g) + e⁻ IE₁ = 731 kJ/mol
In this reaction, a solid silver atom loses one electron to form a silver ion (Ag⁺) in the gas phase. The energy required for this process is 731 kilojoules per mole.
By comparison, the first ionization energy of rubidium (Rb) is approximately 403 kJ/mol. This is significantly lower than that of silver.
At first glance, this may seem surprising if one were only considering periodic trends. Rubidium is located in Group 1 (alkali metals), while silver is in Group 11 (transition metals). Periodic trends indicate that ionization energy increases across a period from left to right and decreases down a group. Rubidium is in Period 5, and so is silver, but rubidium is farther to the left on the periodic table.
Following this trend, one would predict that silver, being farther to the right, should have a higher ionization energy than rubidium—and this is exactly what we observe. Silver holds onto its outer electron more tightly due to its greater effective nuclear charge and smaller atomic radius compared to rubidium.
Furthermore, rubidium has a single valence electron in the 5s orbital that is farther from the nucleus and more shielded by inner electrons. This makes it easier to remove than silver’s 5s¹ electron, which experiences a higher effective nuclear attraction due to the electron configuration [Kr]4d¹⁰5s¹.
Therefore, based on periodic trends and atomic structure, the observed relationship is consistent with predictions, and silver’s higher ionization energy compared to rubidium makes sense.
