Question

Which block of the periodic table contains clements whh the general clectronic configuration \((n-2) f^{i-14}(n-1) d^{0-1} n s^{2} ?\) (4) stolock (b) \(p\)-block (c) d-block (d) \(f\)-block

Short answer

(d) f-block

Step-by-step solution

Define the General Electronic Configuration

The general electronic configuration provided is \( (n-2) f^{1-14}(n-1) d^{0-1} n s^{2} \). This configuration must be correlated with the position of elements in the periodic table.

Identify the Block by the Configuration

In the periodic table, the block of an element is identified by the subshell that is being filled by electrons in the outermost energy level. Here, the presence of \(f^{1-14}\) orbitals indicates that the \(f\)-subshell is being filled with electrons.

Confirm the Block with the Given Sequence

Since the electrons are filling the \(f\)-orbitals in the given configuration, the elements that have such a configuration belong to the \(f\)-block of the periodic table.

Key concepts

Understanding the Periodic Table

The periodic table is not just a randomly organized chart; it's a systematic representation of the elements based on their atomic structure and properties. One of the most distinguishing features it presents is the division into blocks, named after the characteristic orbitals that the electrons occupy. This categorization includes the s-block, p-block, d-block, and the f-block.

Each block corresponds to the filling of a certain type of atomic orbital. For instance, the s-block includes elements with their outermost electrons in s orbitals, while the d-block comprises transition metals with d orbitals being filled. The concept of blocks in the periodic table is crucial as it helps us predict and understand the chemical behavior of elements by considering their electron arrangements.

Decoding Electronic Configuration

Electronic configuration lays out the arrangement of electrons in an atom's orbitals, and understanding this is key to grasping the properties of elements. The configuration \( (n-2) f^{1-14}(n-1) d^{0-1} n s^{2} \) denotes which orbitals the electrons are filling.

The term \( n \) represents the principal quantum number associated with the energy level of the electron. The \( n-2 \) portion of the configuration highlights the filling of f orbitals, which are two levels below the atom's highest energy level. The number of electrons in these orbitals can range from 1 to 14, as indicated by \( f^{1-14} \). In contrast, the \( (n-1) d^{0-1} \) signifies that at most one electron may occupy the d orbital of the energy level just below n. And finally, \( n s^{2} \) suggests the presence of two electrons in the s orbital of the outermost energy level. This configuration is indicative of elements in the f-block.

Lanthanides and Actinides: Digging into the f-block

The f-block of the periodic table is fascinating due to its two series of elements: lanthanides and actinides. Both series are known for their complex electron configurations and unique properties.

• Lanthanides are the 14 elements from cerium (Ce) to lutetium (Lu) that follow lanthanum on the periodic table. They are known for their increasing use in technology, notably in magnets, lasers, and phosphors.
• Actinides follow actinium and include elements like uranium (U) and plutonium (Pu), extending to those only synthesized in the lab. Many actinides are radioactive and have significant nuclear applications.

The intricate electron configurations of these f-block elements play a vital role in their chemistry, leading to their unique magnetic, catalytic, and luminescent properties. The exercise reveals that elements with the given configuration belong to the f-block, encompassing both the lanthanides and actinides, which significantly contribute to the diversity found within the periodic table.