Modern Periodic Law

Define modern periodic law.

Modern Periodic law is the science of the periodic tables. The basic idea is that the elements are not just a random selection of chemicals that have been found but are related to each other in specific ways.

The basic structure for Modern Periodic Law came from Dmitri Mendeleev. Dmitri Mendeleev was born in 1834 and died in 1907. He made a table with all the elements, arranging them in rows and columns corresponding to their properties. He did this without any real theory as to why they were arranged like this, but he was correct in thinking that elements were related in some way that could be recorded.

In 1869, Lothar Meyer and Stanislao Cannizzaro developed a more advanced version of the periodic table, adding columns for properties such as atomic mass and valence.

The development of the periodic table continued when French chemist Alexandre Beguyer de Chancourtois created the first chart with gaps between the elements. This made it clear that there were gaps where no elements had yet been discovered.

Modern Periodic Law Definition

Periodic law is defined as the principle that elements in the same group have similar physical and chemical properties. They have similar outer electron configurations and some electrons in their valence shells.

The periodic table of elements is a chart that organizes elements into rows (called periods) and columns (called groups). The modern periodic law definition is based on these groupings. A large number of elements can be seen under each group. The modern periodic law was first proposed by Dmitri Mendeleev in 1869 and revised in 1871, but it is based on many centuries worth of discoveries about chemical elements.

The Modern Periodic Table

The periodic table is an arrangement of elements. It arranges the chemical elements in an order that shows their similarities and helps us to understand them better. It has been derived in an effective, scientific manner. The basic structure of the periodic table consists of several rows with columns. These columns tell us about the atomic number or the spectrum identity information of each element and the type, location, and radius of electron shells around the nucleus. The rows are known as periods, and the columns are known as groups. As per modern principles, ‘n’ represents a period, and ‘Z’ represents group number. From 1, 2…18 indicates the first to 18th period, respectively.

The Modern Periodic Table is an up-to-date list of the 118 known chemical elements. It organizes them by increasing the atomic number (number of protons in the nucleus), arranged alphabetically. The Modern Periodic Table also includes the newly discovered element 117 and has room for seven more elements that have yet to be discovered.

Tables of elements have been around since the 18th century when John Dolan first published one in his book The Metaphysical-Theological Discourse. In 1829, Jöns Jakob Berzelius published a similar table listing 65 elements, and he also introduced many new symbols for chemical elements. Berzelius’s table served as a model for all of its successors until Mendeleev published his table in 1869.

Tables of elements are useful because they give scientists a quick way to look up information about the atomic weight or density or melting or boiling point of a particular chemical element. Chemists can also plan experiments or predict the products they might obtain when combining different elements in a lab setting.

Law of Modern Periodic Table

The Law of the Modern Periodic Table is that two elements are rarer than the rest, directly opposite each other. This law was found while classifying the periodic table.

The Law of Modern Periodic Table states that two elements in a group (row) are rarer than the others in that group. For example, Pt is the rarest element in group 4, and Ru is in group 5.

This law was created by spot-checking each row of the periodic table and counting how many times each element occurred. The results showed that all groups have a set pattern followed by all except for a few small exceptions. The pattern is always, 1st and 2nd row: 8+, 3rd row: 8+, 3rd and 4th row: 7+, 5th and 6th row: 7+. There are only two exceptions to this rule: the first and second rows contain eight elements, while the third and fourth rows contain seven elements which is the smallest amount out of all rows.

This law only applies to modern periodic tables, not to older periodic tables, such as Dmitri Mendeleev’s. It also only applies to stable elements.

Classification of the Elements in the Periodic Table:

• Noble gas elements: Noble gas elements are chemical elements with full valence shells, and hence they seldom form chemical compounds. They are also called inert gasses. Noble gas elements do not normally form compounds as they have filled valence shells. However, they can give an exception if mixed with other elements or under high-pressure conditions.

• Representative elements: The Figurative elements can be identified by the number of electrons in their outermost shell. These are:

S-block elements: 2, 8 and 18 electrons

P-block elements: 1, 3, 5, 7, 9 and 15 electrons

The s-block elements have an ns2np1 or ns2np2 outermost configuration. The p-block elements have an ns2np3 or ns2np4 outermost configuration.

• Transition elements: The transition elements are groups 3 to 12 (3-12). The atoms of these elements have their outer electron configuration as (n-1)d1-10ns1-2. The elements are all solid at room temperature. The transition elements have their characteristics, and hence they are also known as “d” block elements. These elements show similarities in physical and chemical properties with each other. They also have similarities in their electronic configuration or outermost shell.

• Inner transition elements: The inner transition elements are the chemical elements in the first and second periods in the periodic table that have an incomplete d- or f-shell and may exhibit valence non-bonding electrons. The series can be divided into two groups: the lanthanides, which have an incomplete d-shell, and the actinides, which have an incomplete f-shell. In some treatments, both groups are subsets of the lanthanide series.

Conclusion: 

In this study material, we have discussed modern period law and its classification. We have also learned about the modern periodic table and its laws. Along with that, we had also classified the elements in a modern periodic table in detail.