Class 10 Science - Chapter 5: Periodic Classification of Elements Class 10 Science - Chapter 5: Periodic Classification of Elements 1. Introduction The periodic table is a tabular arrangement of elements based on their atomic number , electronic configuration , and chemical properties . The classification of elements helps in understanding the trends and periodic properties of elements. 2. Early Attempts at Classification 1. Dobereiner's Triads : Grouped elements into triads (groups of three) with similar properties. The atomic mass of the middle element was approximately the average of the other two. Example: Lithium (Li) , Sodium (Na) , Potassium (K) . 2. Newlands' Law of Octaves : Arranged elements in increasing order of atomic mass. Observed that every 8 th element had propertie...

Class 10 Science - Chapter 4: Carbon and Its Compounds Class 10 Science - Chapter 4: Carbon and Its Compounds 1. Introduction to Carbon Carbon is the 4 th most abundant element in the universe and the 15 th most abundant element in the Earth's crust. Atomic number of carbon : 6 Electronic configuration : 2, 4 Carbon achieves stability by sharing electrons, forming covalent bonds . 2. Why Carbon is Unique 1. Catenation : Carbon can form long chains, branched chains, and rings by bonding with other carbon atoms. Example: Ethane (C 2 H 6 ), Propane (C 3 H 8 ), Benzene (C 6 H 6 ). 2. Tetravalency : Carbon can form 4 covalent bonds with other atoms (e.g., hydrogen, oxygen, nitrogen, etc.). Example: Methane (CH 4 ), Carbon tetrachloride (CCl 4 ). 3. Formation of Multiple Bonds : Carbon can form single (C-C) , double (C=C) , or triple (C≡C)...

Class 10 Physics MCQs Class 10 Physics MCQs Here are 30 Multiple Choice Questions (MCQs) for Class 10 Physics based on the NCERT syllabus . These questions cover topics from Light – Reflection and Refraction , Human Eye and the Colorful World , Electricity , and Magnetic Effects of Electric Current . Light – Reflection and Refraction 1. The image formed by a plane mirror is: a) Real and inverted b) Virtual and erect c) Real and erect d) Virtual and inverted 2. The focal length of a concave mirror is 20 cm. Its radius of curvature is: a) 10 cm b) 20 cm c) 40 cm d) 5 cm 3. A concave mirror forms a real and inverted image of an object at a distance of 40 cm from the mirror. If the object is placed at 20 cm from the mirror, the image will be: a) Real and inverted b) Virtual and erect c) Real and e...

Class 10 Science MCQs Class 10 Science MCQs Here are 20 Multiple Choice Questions (MCQs) for Class 10 Science based on the CBSE syllabus. These questions cover topics from Physics, Chemistry, and Biology. Physics 1. What is the SI unit of electric current? a) Volt b) Ampere c) Ohm d) Watt Answer: b) Ampere 2. Which of the following is NOT a renewable source of energy? a) Solar energy b) Wind energy c) Coal d) Hydropower Answer: c) Coal 3. The focal length of a convex mirror is 20 cm. Its radius of curvature is: a) 10 cm b) 20 cm c) 40 cm d) 5 cm Answer: c) 40 cm 4. Which of the following materials is the best conductor of electricity? a) Wood b) Copper c) Rubber d) Plastic Answer: b) Copper ...

Class 10 Science MCQs Class 10 Science MCQs Note: Answers are in page 4 1. Which of the following is a balanced chemical equation? a) H₂ + O₂ → H₂O b) 2H₂ + O₂ → 2H₂O c) H₂ + 2O₂ → H₂O₂ d) 2H₂ + 2O₂ → 2H₂O 2. The pH of a neutral solution at 25°C is: a) 0 b) 7 c) 14 d) 1 3. Which of the following metals does not react with cold water? a) Sodium b) Calcium c) Magnesium d) Potassium 4. The functional group present in ethanol is: a) –CHO b) –COOH c) –OH d) –CO 5. Which of the following is not a life process? a) Respiration b) Reproduction ...

Class 10 Maths MCQs Class 10 Maths MCQs Here are 30 Multiple Choice Questions (MCQs) for Class 10 Mathematics based on the NCERT syllabus . These questions cover topics from all chapters. Real Numbers 1. The HCF of 96 and 404 is: a) 4 b) 6 c) 8 d) 12 2. Which of the following is an irrational number? a) √9 b) √25 c) √2 d) √16 3. The decimal expansion of 13/625 will terminate after how many decimal places? a) 1 b) 2 c) 3 d) 4 Polynomials 4. The zeroes of the polynomial \( x^2 - 3x - 4 \) are: a) 1, -4 b) -1, 4 c) 3, -4 d) -3, 4 5. If one zero of the quadratic polynomial \( x^2 + 3x + k \) is 2, then the value of \( k \) is: a) -10 b) 10 c) -5 d) 5 6....