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Q: How many valence electrons does helium have? Read this paragraph and choose the correct option from the provided answers: Helium may seem to be an exception, since it has only two valence electrons. This has to do with the fact that the n = 1 energy level has one s orbital and no p orbitals. As a result, the first energy level can be completely filled by just two electrons. It is the presence of a filled valence shell that gives noble gases their unusual stability, not anything intrinsic about the number 8. In addition to helium, the first few elements such as lithium, beryllium, and boron, have a particularly stable configuration with a pair of valence electrons rather that an octet. Choices: - Five - six - three - two A:
(Answer)
two

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Q: In plants and algae where does photosynthesis takes place in? Read this paragraph and choose the correct option from the provided answers: In plants and algae, photosynthesis takes place in chloroplasts. (Photosynthetic bacteria have other structures for this purpose. ) A chloroplast is a type of plastid, or plant organelle. It contains the green pigment known as chlorophyll . The presence of chloroplasts in plant cells is one of the major ways they differ from animal cells. You can see chloroplasts in plant cells Figure below . Choices: - cell wall - nucleus - cytoplasm - chloroplasts A:
(Answer)
chloroplasts

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Q: What is the electrode at which reduction occurs called? Read this paragraph and choose the correct option from the provided answers: The electrode at which reduction occurs is called the cathode . The cathode gradually increases in mass because of the production of copper metal. The concentration of copper(II) ions in the half-cell solution decreases. The cathode is the positive electrode. Choices: - reducthode - anode - cathine - cathode A:
(Answer)
cathode