which of the following is the basis for rutherford's planetary model?

a. positively charged electrons orbit a positively charged nucleus.
b. positively charged electrons orbit a negatively charged nucleus.
c. negatively charged electrons orbit a positively charged nucleus.
d. negatively charged electrons orbit a negatively charged nucleus.

Consider the nuclear equation below. 239/94 pu—-> x+ 4/2 he. what is x?

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.

One similarity and one difference between an element and a mixture of elements