Class 10 Chemistry Worksheet – Periodic Classification of Elements

Chemistry is a fascinating subject that helps us understand the composition and behavior of substances around us. One of the most important concepts in chemistry is the Periodic Classification of Elements. This topic introduces students to the systematic arrangement of elements based on their properties. Learning about the periodic table not only enhances our understanding of elements but also helps in predicting their behavior in chemical reactions.

This article focuses on the chapter Periodic Classification of Elements from Class 10 Chemistry, breaking it down into key concepts and providing a detailed worksheet to help students reinforce their learning.

What is Periodic Classification of Elements?

The Periodic Classification of Elements is the process of arranging elements in a systematic order based on their properties. This arrangement makes it easier to study and understand their chemical and physical behaviors.

The periodic table, developed by Dmitri Mendeleev, has evolved over time and is now organized based on increasing atomic numbers. This modern arrangement provides insights into the relationships between various elements.

Importance of the Periodic Table

1. Simplifies Study of Elements: The periodic table groups elements with similar properties together, making them easier to study.
2. Predicts Properties: It helps predict the chemical and physical properties of elements.
3. Facilitates Chemical Reactions: Understanding the periodic table makes it easier to predict how elements will react with each other.
4. Foundation of Modern Chemistry: The periodic table is the backbone of chemistry, connecting different concepts.

Key Concepts in Periodic Classification

1. Dobereiner’s Triads: Johann Wolfgang Dobereiner grouped elements into triads based on their properties. For example:
   • Lithium (Li), Sodium (Na), and Potassium (K)
   • The atomic mass of the middle element was the average of the other two.
2. Newlands’ Law of Octaves: John Newlands arranged elements in increasing order of atomic masses. He noticed that every eighth element had similar properties, like the notes in music. However, this law was limited to lighter elements.
3. Mendeleev’s Periodic Table: Dmitri Mendeleev arranged elements based on their atomic masses and left gaps for undiscovered elements. His table successfully predicted properties of new elements.
4. Modern Periodic Table: The modern periodic table is based on increasing atomic numbers. It consists of:
   • Groups: Vertical columns (1 to 18)
   • Periods: Horizontal rows (1 to 7)

Do Check: Periodic Classification of Elements Class 10 Notes Science Chapter 5

Worksheet for Periodic Classification of Elements Class 10

The following worksheet is designed to help Class 10 students practice and understand the periodic classification of elements. This worksheet covers various aspects, including definitions, examples, and application-based questions.

Section A: Fill in the Blanks

1. The modern periodic table is arranged based on increasing ________.
2. Elements in the same ________ have similar chemical properties.
3. Mendeleev left gaps in his periodic table for ________ elements.
4. ________ law states that the properties of elements are a periodic function of their atomic masses.
5. The horizontal rows in the periodic table are called ________.

Section B: Match the Following

Section C: True or False

1. All elements in a group have the same number of valence electrons.
2. Mendeleev’s periodic table was based on atomic numbers.
3. The periodic table has 18 periods.
4. Noble gases belong to Group 18.
5. Elements in Period 2 have a maximum of two shells.

Section D: Short Answer Questions

1. Define the modern periodic law.
2. Why are elements arranged in groups and periods?
3. What are metalloids? Name any two metalloids from the periodic table.
4. Explain why Mendeleev left gaps in his periodic table.
5. How does the reactivity of metals and non-metals change across a period?

Do Check: Periodic Classification of Elements MCQ for NEET

Section E: Application-Based Questions

1. Valency Prediction:
   An element belongs to Group 1, Period 3.
   • What is its atomic number?
   • What is its valency?
   • Name the element.
2. Metallic Character:
   Compare the metallic character of elements in Group 1 (Li, Na, K).
3. Position in Periodic Table:
   Element X has an atomic number of 15. Determine:
   • Its group number
   • Its period number
   • Its valency
4. Chemical Reactivity:
   Explain why the reactivity of halogens decreases as we move down the group.

Section F: Long Answer Questions

1. Explain the evolution of the periodic table from Dobereiner’s triads to the modern periodic table.
2. Discuss the trends in the following properties across a period and down a group:
   • Atomic size
   • Metallic character
   • Ionization energy
3. Describe how the periodic table helps in understanding the properties of elements.

Section G: Activity-Based Learning

1. Group and Period Identification
   • Look at the periodic table and identify the group and period of the following elements:
     • Magnesium (Mg)
     • Sulfur (S)
     • Argon (Ar)
2. Trends in Atomic Radius
   • Draw a diagram showing the trend of atomic radius across Period 2 and Group 1.
3. Valence Electron Configuration
   • Write the valence shell electronic configurations for the following:
     • Sodium (Na)
     • Chlorine (Cl)
     • Calcium (Ca)

Do Check: NCERT Solutions for Class 10 Science Chapter 5 Periodic classification of elements

Section H: Multiple Choice Questions (MCQs)

1. The element with atomic number 12 belongs to:
   a) Group 1, Period 3
   b) Group 2, Period 3
   c) Group 13, Period 2
   d) Group 16, Period 2
2. Which of the following has the highest electronegativity?
   a) Fluorine
   b) Chlorine
   c) Oxygen
   d) Sulfur
3. In which group do noble gases belong?
   a) Group 1
   b) Group 17
   c) Group 18
   d) Group 2
4. The metallic character increases:
   a) Across a period
   b) Down a group
   c) Both a and b
   d) Neither a nor b
5. Which of the following is not a metalloid?
   a) Silicon
   b) Boron
   c) Germanium
   d) Potassium

Section I: Practical Applications of Periodic Classification

1. Discuss how periodic trends help in predicting the type of bonding in compounds.
2. Explain how the periodic table is used in industrial applications to select materials for specific purposes.
3. Explore the use of noble gases in real-life applications.