He realized that the physical and chemical properties of elements<span> were related to their atomic mass in a '</span>periodic<span>' way, and </span>arranged<span> them so that groups of </span>elements<span> with similar properties fell into vertical columns in </span>his table<span>.
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Moles of MgF₂ : 1.2 x 10⁻⁴
<h3>Further explanation</h3>
Maybe the complete question is like this
<em>A student prepares 100. mL of a saturated solution of MgF2 by adding 0.50 g of solid MgF2 to 100. mL of distilled water at 25°C and stirring until no more solid dissolves. (Assume that the volume of the undissolved MgF2 is negligibly small.) The saturated solution is analyzed, and it is determined that [F−] in the solution is 2.4 × 10−3 M. </em>
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The dissociation reaction of MgF₂
MgF₂(s)⇒ Mg²⁺(aq)+2F⁻(aq)
mol ratio MgF₂ : F⁻ = 1 : 2
mol of F⁻ in 100 ml solution :

mol MgF₂ :

Answer: sound can slow down, so when it travels through all of that it's muffled and kind of blocked. sound travels at 332 metres per second so it's hard to stop the sound
Explanation:
The dense aerosol cloud created caused decreases in the amount of solar radiation that reached the Earths surface.