Answer:
The noble gases have 8 valence electrons in their outermost electron shell. In other words, they have full out shells. These elements are highly stable.
Answer:
C. H:C:H:H
Explanation:
Follow these simple steps to correctly draw a Lewis dot structure: Add up the total number of valence electrons found in the entire compound. Draw the simple structure (skeleton structure) of the compound by connecting everything with single bonds only. Add electrons to all the noncentral atoms. Put any unused electrons on the central atom.
i. The dissolution of PbSO₄ in water entails its ionizing into its constituent ions:

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ii. Given the dissolution of some substance
,
the Ksp, or the solubility product constant, of the preceding equation takes the general form
.
The concentrations of pure solids (like substance A) and liquids are excluded from the equilibrium expression.
So, given our dissociation equation in question i., our Ksp expression would be written as:
.
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iii. Presumably, what we're being asked for here is the <em>molar </em>solubility of PbSO4 (at the standard 25 °C, as Ksp is temperature dependent). We have all the information needed to calculate the molar solubility. Since the Ksp tells us the ratio of equilibrium concentrations of PbSO4 in solution, we can consider either [Pb2+] or [SO4^2-] as equivalent to our molar solubility (since the concentration of either ion is the extent to which solid PbSO4 will dissociate or dissolve in water).
We know that Ksp = [Pb2+][SO4^2-], and we are given the value of the Ksp of for PbSO4 as 1.3 × 10⁻⁸. Since the molar ratio between the two ions are the same, we can use an equivalent variable to represent both:

So, the molar solubility of PbSO4 is 1.1 × 10⁻⁴ mol/L. The answer is given to two significant figures since the Ksp is given to two significant figures.
To be honest the answer should be B. Hope this help.