Which of the following particles has the largest mass? A neutron a proton a beta

Question

Which of the following particles has the largest mass? A neutron a proton a beta particle an alpha particle a positron Fluorine-18 is radioactive (positron emission) and has a half-life a 100 minutes. If 40mg of fluorine-18 is isolated at a certain time, how much will remain undecayed five hours (300 minutes) later? 20 mg 10 mg 5 mg 2.5 mg none What is the missing nuclide in the following fission reaction? iodine-127 iodine-131 iodine-134 indium-131 indium-134 What nucleus decays by an alpha (a) emission followed by two successive beta (beta) emissions to produce polonium-214? polonium-218 radium-218 polonium-210 francium-222 radon-222 Aluminum-27 is the only stable isotope of aluminum. What is the most probable mode of nuclear decay for aluminum-30? alpha emission beta emission positron emission electron capture gamma emission

Explanation / Answer

51. D) Alpha particle.

An alpha particle 42He has the largest mass of all of them (mass = 4amu). A neutron and proton's mass are = 1amu, the electron, positron and beta particle masses are nearly zero.

52. C) 5mg

At t=0 we have 40mg, at t=100min we would have 40mg/2 = 20mg, at t=200min we would have 20mg/2 = 10mg and a t=300min we would have 10mg/2 = 5mg

53. B) Iodine-131

The balance of Z (atomic number) says there must be 92 protons on each side of the equation, if we solve for the protons of the nuclide Z+39=92 then we would know Z=53 (atomic number for iodine).

The balance of A (mass number) says there must be 236 on each side of the equation, if we solve for the mass of the nuclide A+101+4(1)=236 then we would know A=131

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