Answer: The correct option is 3.
Explanation: Radioisotopes that emit alpha-particles are termed alpha-emitters. These isotopes undergo alpha-decay.
Those radioisotopes that emit beta-particles 
are called beta-emitters. They undergo beta-minus decay, in which a neutron converts to a proton and an electron.
Isotopes that emit positrons 
are known as positron-emitters, undergoing beta-plus decay where a proton becomes a neutron.
From the options given,
Option 1: All three isotopes undergo beta-minus decay.
Option 2: Cs-137 and Tc-99 undergo beta-minus decay.
Fr-220 undergoes alpha-decay.
Option 3: Kr-85 undergoes beta-minus decay.
Ne-19 undergoes positron decay.
Rn-222 undergoes alpha decay.
Option 4: All three isotopes undergo beta-minus decay processes.
Therefore, the correct choice is 3.
The appropriate answer is option E. Gibbs free energy can be expressed using the equation: ΔG = ΔH - TΔS, where ΔH denotes the change in enthalpy of the reaction, T is the reaction temperature, and ΔS signifies entropy change. For our calculations, we have ΔH = -720.5 kJ/mol which converts to -720500 J/mol (given that 1 kJ = 1000 J), ΔS = -263.7 J/K, and T = 141.0°C, which equals 414.15 K. Consequently, the Gibbs free energy for the specified reaction at 141.0°C is calculated as -611.3 kJ/mol.
84.34 grams of iron (III) chloride is the maximum produced since iron is the limiting reagent, and chlorine gas is in excess.
Explanation:
Balanced equation:
2 Fe + 3 Cl2 → 2 FeCl3
DATA PROVIDED:
iron = atoms
mass of chlorine = 67.2 liters
mass of FeCl3 =?
The number of moles of iron will be calculated as
number of moles = 
number of moles = 
number of moles = 0.52 mol of iron
moles of chlorine gas
number of moles = 
Substituting the values into the equation:
n = 
(molar mass of chlorine gas = 70.96 g/mol)
= 947.01 moles
As iron is the limiting reagent therefore
2 moles of Fe lead to 2 moles of FeCl3
0.52 moles of Fe will yield
= 
0.52 moles of FeCl3 is produced.
To express this in grams:
mass = n x molar mass
= 0.52 x 162.2 (molar mass of FeCl3 is 162.2g/mol)
= 84.34 grams
Answer:
Chemists observe phenomena on a macroscopic level which informs their understanding of microscopic aspects.
Explanation:
Many critical chemical insights arise from macroscopic observations because most scientific instruments currently cannot directly evidence microscopic events. Data gathered from these larger-scale observations can yield valuable insights into the nature of specific microscopic interactions.
This is particularly true in atomic structure studies. The majority of evidence that contributed to our understanding of atomic structure was obtained from macroscopic observations and subsequently provided crucial information regarding the atom's microscopic configuration.
