Periodic Table Full Explanation for NEET Chemistry

Periodic Table: Full Explanation for NEET & Chemistry Students

The periodic table is one of the most important tools in chemistry. It is a systematic arrangement of all known elements based on their atomic number, electronic configuration, and recurring chemical properties. Understanding the periodic table is essential for mastering chemistry for NEET, JEE, and board exams.

History of the Periodic Table

• Dmitri Mendeleev (1869): Proposed the first periodic table based on atomic masses. He left gaps for undiscovered elements.
• Henry Moseley (1913): Modified the periodic table based on atomic numbers, which is the basis of the modern periodic table.

This led to the Modern Periodic Law: "The physical and chemical properties of elements are a periodic function of their atomic numbers."

Structure of the Modern Periodic Table

The modern periodic table consists of:

• 7 Periods (horizontal rows)
• 18 Groups (vertical columns)
• 4 Blocks: s-block, p-block, d-block, f-block

There are 118 confirmed elements as of now, ranging from Hydrogen (H) to Oganesson (Og).

Classification of Elements

s-Block Elements

• Group 1 (Alkali metals) and Group 2 (Alkaline earth metals)
• Highly reactive metals, low ionization energy

p-Block Elements

• Groups 13 to 18
• Includes metals, metalloids, and non-metals
• Contains halogens (Group 17) and noble gases (Group 18)

d-Block Elements (Transition Elements)

• Groups 3 to 12
• Exhibit variable oxidation states
• Form colored compounds

f-Block Elements (Inner Transition Elements)

• Lanthanides and Actinides
• Mostly radioactive and synthetic

Periodic Trends in the Periodic Table

1. Atomic Radius

• Across a period: Decreases
• Down a group: Increases

2. Ionization Energy

• Across a period: Increases
• Down a group: Decreases

3. Electronegativity

• Across a period: Increases
• Down a group: Decreases

4. Metallic and Non-metallic Character

• Metals are found on the left; non-metals on the right
• Metallic character increases down the group, decreases across the period

5. Electron Affinity

• Across a period: Increases
• Down a group: Decreases

Important Groups and Their Names

Group Number	Name	Example Elements
1	Alkali Metals	Li, Na, K
2	Alkaline Earth Metals	Mg, Ca
17	Halogens	F, Cl, Br
18	Noble Gases	He, Ne, Ar

Importance of Periodic Table in NEET

• Direct MCQs are asked on groups, periods, and blocks
• Trends like electronegativity, ionization energy are commonly tested
• Helps in predicting chemical behavior

Example NEET Question:

Which of the following elements has the highest electronegativity?

• (A) Sodium
• (B) Fluorine
• (C) Chlorine
• (D) Oxygen

Answer: (B) Fluorine

Tips to Memorize the Periodic Table

1. Use mnemonics like: “Hi He Likes Beer But Could Not Offer Full Nine Softies” for 1st 10 elements.
2. Make a colorful wall chart and revise daily.
3. Focus on groups and periods, not just atomic numbers.
4. Practice NEET-based MCQs daily.

Conclusion

The periodic table is the backbone of chemistry. Whether it's identifying elements, understanding trends, or predicting reactions, the periodic table is essential. For NEET aspirants, mastering this topic is non-negotiable. Keep revising and practicing questions based on periodic trends and properties.

Explore more NEET Chemistry topics at Chemistry of Science.