D. The number of electrons equals the atomic number for a neutral element. Each number after the letter refers to the number of electrons in that shell. So for D, 2+2+6+2+6+2 = 20 electrons, which is equal to the atomic number.
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Explanation:
This is a bond with reacts with metal's
Answer:
Lichens can be used as air pollution indicators, especially of the concentration of sulphur dioxide in the atmosphere. Lichens are organisms that grow in exposed places such as rocks or tree bark. They need to be very efficient at absorbing water and nutrients to grow there.
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Explanation:
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In this case, since the molarity of a solution is calculated by diving the moles of solute by the volume of solution in liters, we first compute the moles of barium hydroxide in 35.5 g as shown below:

Then, the liters of solution:

Finally, the molarity turns out:

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Since there's specific heat, you should use Q=mc△T. Depends on if this question also involves phase change or not, you might will need Lf (latent heat of fusion) or Lv (latent heat of vaporisation).