Answer: Melatonin has been used safely for up to 2 years in some people. However, it can cause some side effects including headache, short-term feelings of depression, daytime sleepiness, dizziness, stomach cramps, and irritability. Do not drive or use machinery for four to five hours after taking melatonin.
<span>The alkali metals and hydrogen are reactive because they have only one electron to give in order to complete their valence shell. It is easier to give that one electron so when given the opportunity they will. This means they will react with anything polar or willing to take an electron.</span>
I believe the correct answer from the choices listed above is the third option. It would be chromium (Cr) that is a transition metal. The 38 elements in groups 3 through 12 of the periodic table are called "transition metals<span>". Hope this answers the question. Have a nice day.</span>
11. a. Amphoteric
12. a. NH₄⁺, H₂O
Explanation:
11. A substance that can act as either an acid or a base is said to be <u>amphoteric</u>.
Water is an amphoteric substance because it can reaction with either and acid or a base.
HCl + H₂O → Cl⁻ + H₃O⁺
NH₃ + H₂O → NH₄⁺ + OH⁻
12. What are the acids in the following equilibrium reaction?
NH₃ (aq) + H₂O (l) → NH₄⁺ (aq) +OH⁻ (aq)
H₂O water is acid 1
NH₄⁺ ammonium ion is acid 2
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amphoteric substances
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The highest sequence for this shell is the number 2, preceding both the s and p in the diagram. This means that the outermost shell is the second level shell. In this shell, there are 7 electrons, 2 in the 2s orbital and 5 in the 2p orbital.
As a side note (not sure if this is a typo), the electron structure for fluorine begins with a 1s2, not a 1s1.
