Answer:
Barium has a larger atomic radius because it has more energy levels and a larger shielding effect. Silicon has a smaller atomic radius because it has a stronger nuclear charge. Since chlorine's 17 protons are greater than magnesium's 12 protons, chlorine will have a greater effective nuclear charge to draw chlorine's valence electrons closer to the nucleus and, thus, chlorine is expected to have the smaller atomic radius, while magnesium with the lower effective nuclear charge is expected to.
You have not specified any indication of volume, but I will assume this is in a vessel of 1.00 L.
If 0.0100 mole of H+ is added to this buffer, then in the equilbrium
<span> NH3+H2O ⇄ NH4+ + OH-
the H+ reacts with OH- and decreases [OH-] and shifts the equilibrium to the products. [NH4+] will increase by 0.0100 M and [NH3] will decrease by 0.0100M. So the new concentrations are [NH4+] = 0.110 M and [NH3] = 0.09 M. Then
[OH-] = [NH3]/[NH4+] * Kb</span>
= 0.09/0.110 *1.8*10^-5
<span> = 1.47 x 10^-5
and pOH = -log(</span><span>1.47 x 10^-5) = 4.8318.
Since pH + pOH = 14,
pH = 14 - 4.8318 = 9.168
The answer to this question is therefore 9.168.</span>
It would have a positive two charge (+2).
12+(-12)=0
12+(-10)=2