(Question)
Q: Limestone is insoluble in water, so what can dissolve it? Read this paragraph and choose the correct option from the provided answers: An element is a substance that cannot be broken down into chemically simpler components. Compounds can be broken down into simpler substances. Choices: - calcium - dioxide - oxygen - acid A:
(Answer)
acid

(Question)
Q: Which type of electrons plays the most important role in chemical reactions? Read this paragraph and choose the correct option from the provided answers: Electron Configurations and the Periodic Table As described earlier, the periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their electron configurations are added to the table (Figure 6.30), we also see a periodic recurrence of similar electron configurations in the outer shells of these elements. Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. The outer electrons have the highest energy of the electrons in an atom and are most easily lost or shared than the core electrons. Valence electrons are also the determining factor in some physical properties of the elements. Elements in any one group (or column) have the same number of valence electrons; the alkali metals lithium and sodium each have only one valence electron, the alkaline earth metals beryllium and magnesium each have two, and the halogens fluorine and chlorine each have seven valence electrons. The similarity in chemical properties among. Choices: - noncovalent - intermediate - transition - valence A:
(Answer)
valence

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Q: What types of drugs affect the brain and influence how a person can feel, think, or act? Read this paragraph and choose the correct option from the provided answers: Many drugs affect the brain and influence how a person feels, thinks, or acts. Such drugs are called psychoactive drugs. They include legal drugs such as caffeine and alcohol, as well as illegal drugs such as cocaine and heroin. They also include certain medicines, such as antidepressant drugs and medical marijuana. Choices: - antibiotics - analgesics - prescription - psychoactive A:
(Answer)
psychoactive