The atom that would gain two electrons to fill its valence energy level is S(sulfur)
This is because s (sulfur) is in atomic number 16 with 2.8.6 of [Ne] 3s^2 2p^4 electronic configuration. This implies that sulfur has 6 valence electron and therefore it require two electron to fill its valence energy level and obtain 18 rule electrons.
Half life is the time that it takes for half of the original value of some amount of a radioactive element to decay.
We have the following equation representing the half-life decay:

A is the resulting amount after t time
Ao is the initial amount = 50 mg
t= Elapsed time
t half is the half-life of the substance = 14.3 days
We replace the know values into the equation to have an exponential decay function for a 50mg sample

That would be the answer for a)
To know the P-32 remaining after 84 days we have to replace this value in the equation:

So, after 84 days the P-32 remaining will be 0.85 mg
I believe it the answer is 3412
Answer:
102g of crystals
Explanation:
When the Cr(NO₃)₃⋅9H₂O is dissolved in water at 15°C, the maximum mass that water will dissolve in the equilibrium is 208 g per 100g of water. When you heat the water, this mass will increases.
In this problem, at 35°C the water dissolves 310g in 100g of water, as in the equilibrium at 15°C the maximum mass is 208g, the mass of crystals that will form is:
310g - 208g = <em>102g of crystals</em>
<em>-Crystals are the Cr(NO₃)₃⋅9H₂O that is not dissolved-.</em>
I hope it helps!
I know what you're asking but I don't think the question is stated properly. Technically, an atom will not join with an "oxide" ion; i.e., the oxide ion is an atom of oxygen to which two electrons have been added. An oxide ion will add to 2 K ions or 1 Ca ion. The K ion has lost just one electron so it takes two of them to equal the 2- charge on the oxide ion whereas the Ca ion has lost two electrons and it takes only one of them to equal the charge on the oxide ion.