Doubtly
@Doubtly · Joined Feb 2021
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- 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
- give one example of each elements Hydrogen is an example of element 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