Weight of the balloon = 2.0 g
Six weights each of mass 30.0 g is added to the balloon.
Total mass of the balloon = 2.0 g + 6*30.0 g = 182 g
Density of salt water = 1.02 g/mL
Calculating the volume from mass and density:

Converting the volume from mL to cubic cm:

Assuming the balloon to be a sphere,
Volume of the sphere =
π

r = 3.49 cm
Radius of the balloon = 3.49 cm
Diameter of the balloon = 2 r = 2*3.49 cm = 6.98cm
I would expect silane because all the rest have an overall dipole movement
Positive ions are formed by atoms or molecules suffering an inelastic collision with an energetic electron in which an electron is lost from the atom or molecule (electron impact ionization). The degree of ionization of the plasma depends strongly on the electron density and energy distribution in the gas.