NCERT
- What is the function of digestive enzymes? Digestive enzymes such as amylase, lipase, pepsin, trypsin, etc. help in the breaking down of complex food particles into simple ones. These... 1
- What is the role of the acid in our stomach? Following are the roles of acid in our stomach: The hydrochloric acid present in our stomach dissolves bits of food and creates an acidic me... 1
- Where do plants get each of the raw materials required for photosynthesis? The following raw materials are required for photosynthesis: Carbon Dioxide: Plants get CO₂ from atmosphere through stomata. Water: Plants a... 1
- What are the differences between autotrophic nutrition and heterotrophic nutrition? Autotrophic Nutrition Heterotrophic Nutrition Food is synthesised from simple inorganic raw materials such as CO₂ and water. Food is obtaine... 1
- What processes would you consider essential for maintaining life? Life processes such as nutrition, respiration, transportation, excretion, etc. are essential for maintaining life. 1
- What are outside raw materials used for by an organism? Various outside raw materials used by an organism are as follows: Food as source of supplying energy and materials. Oxygen for breakdown of... 1
- What criteria do we use to decide whether something is alive? Any visible movement such as walking, breathing, or growing is generally used to decide whether something is alive or not. However, a living... 1
- Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans? Unlike the unicellular organisms, the multi-cellular organisms have complex body structures with specialized cells and tissues to perform va... 1
- Compare and contrast the arrangement of elements in Mendeleev's Periodic Table and the Modern Periodic Table. Mendeleev's periodic table Modern periodic table Elements are arranged in the increasing order of their atomic masses. Elements are arranged... 1
- In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers The element with atomic number 12 has same chemical properties as that of calcium. This is because both of them have same number of valence... 2
- How does the electronic configuration of an atom relate to its position in the Modern Periodic Table? In the modern periodic table, atoms with similar electronic configurations are placed in the same column. In a group, the number of valence... 1
- Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Nitrogen (7): 2, 5 Phosphorus (15): 2, 8, 5 Since, electronegativity decreases with moving from top to bottom in a group, thus Nitrogen will... 1
- The position of three elements A, B and C in the Periodic Table are shown below - Group 16 Group 17 (a) A is a non-metal. (b) C is less reactive than A, as reactivity decreases down the group in halogens. (c) C will be smaller in size than... 1
- An atom has electronic configuration 2, 8, 7. (a) What is the atomic number of this element? (a) The atomic number of this element is 17. (b) It would be chemically similar to F(9) with configuration as 2, 7. 1
- What property do all elements in the same column of the Periodic Table as fluorine have in common Valency equal to 1. 2
- What property do all elements in the same column of the Periodic Table as boron have in common? Valency equal to 3. 2
- Which element has (a) two shells, both of which are completely filled with electrons? (a) Neon (b) Magnesium (c) Silicon (d) Boron (e) Carbon 2
- Element X forms a chloride with the formula XCl2, which is a solid with a high melting point. Correct option is (b) Mg 2
- Which of the following statements is not a correct statement about the trends when going from left Correct option is (c) The atoms lose their electrons more easily. 1
- By considering their position in the Periodic Table, which one of the following elements Since Be lies to the extreme left hand side of the periodic table, Be is the most metallic among the given elements. 1
- In the Modern Periodic Table, which are the metals among the first ten elements? Among the first ten elements, lithium (Li) and beryllium (Be) are metals. 1
- Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, Both helium (He) and neon (Ne) have filled outermost shells. Helium has a duplet in its K shell, while neon has an octet in its L shell. 1
- Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any Yes. The atoms of all the three elements lithium, sodium, and potassium have one electron in their outermost shells. 1
- Name (c) three elements with filled outermost shells. Neon (Ne), argon (Ar), and xenon (Xe) have filled outermost shells. 1