/ Preparation Chemistry Classification of Elements and Periodicity in Properties
The topic that we are going to cover today is one of the most important topics of chemistry and has a history of being repeatedly asked in competitive exams like JEE MAINS. Studying the properties of chemical elements was far more difficult in ancient times, and there was no proper systematic arrangement of these elements to classify them effectively. So to eliminate this problem, scientists figured out a tabular form of data that comprised all these elements laid properly as per their chemical properties and reactivity, known as the periodic table.
What was this table, and how did it classify all the elements perfectly? Understand deeply through this article.
- What is the Modern Periodic Table?
- Structure of the Periodic Table
- Periods
- Groups
- Blocks
- Importance of the Periodic Table
What is the Modern Periodic Table?
Perioid table is a technique discovered by Mendeleev and Moseley in the 20th century. In this technique, there exists a table where elements are systematically arranged as per their increasing order of atomic mass. Elements are arranged in this table based on three core properties: electronic configuration, chemical properties and reactivity, and atomic number (z).
Structure of the Periodic Table
The periodic table is divided into 7 rows and 18 columns, known as periods and groups respectively. There exist 4 major blocks in the periodic table: s,p,d and f. Properties of elements repeat at fixed intervals if they are arranged according to their atomic mass. Hence it is called a periodic table. Let us dive into detailed aspects of these three sub divisions of the table.
Periods
As we move left to right in a period (by 1), the metallic character of the element increases.
- Period 1:From H(Z=1) to He(Z=2)
- Period 2:From Li (Z=3) to Ne (Z=10)
- Period 3:From Na(Z=11) to Ar(Z=18)
- Period 4:From K (Z=19) to Kr (Z=36)
- Period 5:From Rb (Z=37) to Xe (Z=54)
- Period 6:From Cs (Z=55) to Rn (Z=86)
- Period 7:From Fr (Z=87) to Ha (Z=105)
Groups
Elements in similar groups have similar valence shell electron configuration.
- Group 1: Alkali Metals
- Group 2: Alkaline Earth Metals
- Group 3–12: Transition Metals
- Group 13-18: Noble Gases
Blocks
Classified based on the orbital where the last electron occurs.
- s-block: s-orbital (Group 1-2)
- p-block: p-orbital (Group 13–18)
- d-block: Transition metals
- f-block: Lanthanides & Actinides
Importance of the Periodic Table
This table holds significant value in revolutionizing the way elements are grouped together, with some major reasons listed below:
- It helps to determine properties of the elements.
- It groups all the similar elements together and separates them from other elements that have different properties.
- Scientists can refer to this table for research and experimental purposes.
- You can calculate important trends accurately through this table.
- It holds historical significance, paving a fruitful way for scientists' efforts over the centuries.
Chemistry Classification of Elements and Periodicity in Properties Exam
Student Forum
Anything you would want to ask experts?Other Topics under this Chapter
- Classification of Elements
- Electronic Configuration Types of Elements
- Why do we need to classify elements
- Periodic Trends in Properties of Elements
- Genesis of Periodic Classification
- Present Form of Periodic Table
- Nomenclature of Elements with Atomic Numbers
- Periodic Table Electronic Configuration of Element
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