General Trends in d-block Elements (Atomic Radii, Ionization) The d-block elements, situated between Group 1 and Group 13 in the periodic table, exhibit dist...
The d-block elements, situated between Group 1 and Group 13 in the periodic table, exhibit distinct atomic properties and behaviors. These elements display certain general characteristics, while also exhibiting significant variations.
Atomic Radii:
The atomic radius of d-block elements generally increases down a group due to the increase in atomic number and effective nuclear charge experienced by the electrons. This means the d-orbital with the highest energy level (5d) becomes progressively larger as you move down the group.
For instance, the atomic radius of mercury (Hg) is significantly larger compared to that of sodium (Na), showcasing the relative expansion of the d-orbital as you move down the group.
Ionization:
The ionization energy of d-block elements follows a similar trend to atomic radius. It generally increases down a group due to the increased effective nuclear charge experienced by the electrons. This means that it becomes more difficult to remove an electron from a d-orbital compared to an s-orbital due to the increased effective nuclear charge.
For example, the ionization energy of calcium (Ca) is lower compared to that of magnesium (Mg), indicating that it is easier to remove an electron from the Ca atom.
Examples:
The d-block element with the highest atomic radius is mercury (Hg), with an atomic radius of approximately 140 pm.
The d-block element with the lowest ionization energy is francium (Fr), with an ionization energy of 790 kJ/mol.
Additional Notes:
The d-block elements exhibit variable chemical properties due to the involvement of d-orbitals in their atomic orbitals.
These elements tend to be more reactive compared to the elements in the main group due to the increased effective nuclear charge experienced by the electrons in the d-orbitals.
The d-block elements are the least reactive in the entire periodic table, making them valuable in various applications, including catalysis, semiconductors, and pharmaceuticals