Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The -block elements are found in Groups 3 to 12 of the periodic table, occupying the central part between the -block and -block elements.
A transition element is defined as one which has incompletely filled -orbitals in its ground state or in any one of its common oxidation states.
The -block consists of four series: series ( to ), series ( to ), series (, to ), and series (which is incomplete).
and of group 12 have full configuration in their ground state as well as in their common oxidation states and are therefore not regarded as transition metals.
The -block elements, also known as inner transition elements, consist of two series: Lanthanoids (filling of orbitals) and Actinoids (filling of orbitals), placed separately at the bottom of the periodic table.
The transition elements are so named because their properties represent a transition between the highly electropositive -block elements and the highly electronegative -block elements.
📐Formulae
💡Examples
Problem 1:
On what basis can you say that Scandium () is a transition element but Zinc () is not?
Solution:
Scandium () has the ground state electronic configuration . Since it has an incompletely filled orbital, it is a transition element. Zinc () has the configuration in its ground state and in its oxidation state. Since the -orbitals are completely filled in both cases, it is not a transition element.
Explanation:
The definition of a transition element requires an incomplete -subshell in either the atomic or a common ionic state.
Problem 2:
Silver atom has completely filled orbitals () in its ground state. How can you say it is a transition element?
Solution:
Silver () has the ground state configuration . However, in its common oxidation state (), the configuration becomes .
Explanation:
Because the -orbital is incompletely filled in the oxidation state, Silver satisfies the definition of a transition element.
Problem 3:
Write the general electronic configuration of Lanthanoids.
Solution:
Explanation:
Lanthanoids involve the filling of the subshell. The orbital may contain or electron depending on the stability provided by exchange energy (e.g., Gadolinium).