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In the atom of an element X, 6 electrons are present in the outermost shell. If it acquires noble gas configuration by accepting requisite number of electrons, then what would be the charge on the ion so formed?
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Match the names of the Scientists given in column A with their contributions towards the understanding of the atomic structure as given in column B
| (A) | (B) | ||
| (a) | Ernest Rutherford | (i) | Indivisibility of atoms |
| (b) | J.J.Thomson | (ii) | Stationary orbits |
| (c) | Dalton | (iii) | Concept of nucleus |
| (d) | Neils Bohr | (iv) | Discovery of electrons |
| (e) | James Chadwick | (v) | Atomic number |
| (f) | E. Goldstein | (vi) | Neutron |
| (g) | Mosley | (vii) | Canal rays |
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The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements?
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Helium atom has 2 electrons in its valence shell but its valency is not 2, Explain
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An element X has a mass number 4 and atomic number 2. Write the valency of this element?
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Which of the following are covered by a single membrane?
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Why does the percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere?
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Can you name the two organelles we have studied that contain their own genetic material?
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How do poriferan animals differ from coelenterate animals?
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How do annelid animals differ from arthropods?
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What are the differences between amphibians and reptiles?
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What are the differences between animals belonging to the Aves group and those in the mammalia group?
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How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?
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Explain how animals in Vertebrata are classified into further subgroups.
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Distinguish between the following:
Chromoplast and chloroplast
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Write short note on
Plastids
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What is difference between bilateral symmetry and radial symmetry?
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Write down four characteristics of Ctenophora.
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Write down four main characters of Platyhelminthes.
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Main characteristics of Nematoda:
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