To which group and period do the following elements belong?
a. Carbon (Z=6) Group= Period=
b. neon (Z=10) Group= Period=
c. aluminium (Z=13) Group= Period=
d. Phosphorous (Z=15) Group= Period=
e. Fluorine (Z=9) Group= Period=
f. sulphur(Z=21) Group= Period=
g. Argon(Z=18) Group= Period=

Ok so co(g) is not pronoused that. the only clue is that youpronouse it the oppisote way. 

Answerthis solution will not form a precipitateexplanationsolubility equilbrium:         pbf₂(s)  ⇄ pb²⁺(aq) + 2 f⁻(aq)the solubility product expression is    (we exclude solids from the equilibrium expression).now suppose we have the trial ion product q, which we can define as    then, we can interpret  q as the product of the concentration of the ions that we have and ksp as the product of the ion concentrations that are needed to form a saturated solution.if q > ksp, then that implies that there will be a surplus of ions that exceed the amount that is required to form a saturated solution. a precipitate will then form (the precipitate continually  forms until the surplus ions are removed and q is decreased to ksp's value).if q = ksp, the saturated solution that forms is barely saturated and the precipitate will be minimal.if q < ksp, then the ion concentration will not be enough to form a saturated solution (so no precipitate).using our information, we calculate the trial ion product:     since q = 2.7  × 10⁻⁸ < ksp =  4  ×  10⁻⁸, a precipitate will not form.