Answer:
The answer is below
Explanation:
They are isotopes. Isotopes are molecules that have the same atomic number but have different atomic mass because the number of neutrons is different.
Iodine has an atomic mass of 126 g and its atomic number is 53.
# of neutrons = 126 - 53 = 73
Its isotope has an atomic mass of 128 g its atomic number is also 53, but the number of neutrons is different.
# neutrons = 128 -53 = 75
Answer:
a) excitation radiation
Explanation:
the fluorescence quantum efficiency of the fluorescing molecule:
Molecular structure and its chemical environment influence whether a substance will fluoresce and the intensities of these emissions. The quantum yield or quantum efficiency is used to measure the probability that a molecule will fluoresce or phosphoresce. For fluorescence and phosphorescence is the ratio of the number of molecules that luminescent to the total number of excited molecules. For highly fluoresce molecules, the quantum efficiency approaches to one.Molecules that do not fluoresce have quantum efficiencies that approach to zero.
the molar mass of the compound
Influence of a halogen substitution decreases fluorescence as the molar mass of the halogen increases. This is an example of the “heavy atom effect” which suggest that the probability of intersystem crossing increases as the size of the molecule increases. As the molar mass of the substituted compound increases, the relative intensity of the fluorescence decreases.
The absorptivity of the compound
he molar absorptivity, which measures the probability that a transition will occur
Answer:
n = 0.19 mol
Explanation:
Given mass = 15 g
The molar mass of AsH₃ = 77.94 g/mol
We need to find the number of moles in 15 g of AsH₃. We know that,
No. of moles = given mass/molar mass
So, there are 0.19 g/mol. Hence, the correct option is equal to 0.19 mol.
If I had to answer, I would go with C.) Two elements in the same group
I would choose C because elements in the same group have the same number of valence electrons. When elements have the same number of valence electrons, they are all willing to give/receive them in the same way. Therefore, if placed in water, they will combine with water the same way.
Hope this helps!