Question

What are the merits and limitations of the long form of the periodic table?

Short answer

Answer: The merits of the long form of the periodic table include systematic arrangement, chemical periodicity, electronic configurations, and predicting reactivity. Its limitations consist of size and complexity, separation of lanthanides and actinides, position of hydrogen, and position of helium.

Step-by-step solution

Understand the long form of the periodic table

The long form of the periodic table arranges elements into periods (horizontal rows) and groups (vertical columns) according to their atomic numbers, electronic configurations, and recurring chemical properties. The table contains elements categorized as metals, nonmetals, and metalloids, with further divisions into s-block, p-block, d-block, and f-block elements.

Merits of the long form of the periodic table

The advantages of the long form of the periodic table include: 1. Systematic arrangement: Elements are arranged based on their atomic numbers, allowing for easy identification and study of their properties. 2. Chemical periodicity: The table showcases the periodic repetition of elements with similar properties, making it easier to predict properties of unknown elements or study trends within groups and periods. 3. Electronic configurations: The table is divided into blocks (s, p, d, and f) based on the last electron added in the progressing atomic number, helping in understanding chemical and physical properties of the elements. 4. Predicting reactivity: The long form allows for quick identification of reactivity trends within groups, such as the reactivity of alkali metals increasing down the group, or halogens becoming less reactive as you move down the group.

Limitations of the long form of the periodic table

The disadvantages of the long form of the periodic table include: 1. Size and complexity: The table is extensive, with over 100 elements, making it challenging to remember specific details about each element or trends within their respective groups and periods. 2. Lanthanides and actinides: The f-block elements, including lanthanides and actinides, are separate from the main table, leading to confusion and increasing the complexity of understanding the periodicity. 3. Position of hydrogen: Hydrogen is placed in Group 1 because of its single valence electron, although it exhibits properties of both alkali metals and halogens. This classification creates ambiguity about its placement in the periodic table. 4. Position of helium: Helium has an s2 electronic configuration like other elements in Group 18, but it is placed in Group 18 due to its full-filled electronic configuration like other noble gases, resulting in an exception to the periodic table's structure. By understanding the merits and limitations of the long form of the periodic table, we can appreciate its usefulness and recognize areas where it may fall short or needs modification.