Which of the following elements would decrease in size when it became an ion

Answer:             1.0  × 10⁻⁵ msolution:                     as we know ph is given as,                                    ph  = -log [h⁺]and,                                    [h⁺]  =  10^-ph    (1)putting value of ph in eq. 1,                                    [h⁺]  =  10⁻⁵                                    [h⁺]  =  1.0  × 10⁻⁵ m

Silicon  6.0x10^23 is avogadro's number so the answer has to be 1 mole of whatever it is. since the molarity of silicon is equal to 28g/mol, this has to be the answer because 28g of si is 1 mole of si.