Because there to tiny to see
Answer:
Si una reacción química libera energía, se llama reacción exotérmica. El ejemplo más común es la combustión, en la cual la energía se manifiesta en forma de calor y luz. Si, por el contrario, la reacción química requiere energía del medio para efectuarse, recibe el nombre de reacción endotérmica.
For radioactive decay, we can relate current amount, initial amount, decay constant and time using:
N = No x exp(-λt)
Half-life = ln(2)/λ
λ = ln(2) / 5730
N/No = 80% = 0.8
0.8 = exp( -ln(2)/5730 x t)
t = 1844 years
Answer:
See explanation and image attached
Explanation:
Yttrium has many isotopes, the lowest mass number of Yttrium is 89Y.
Recall that electron capture converts an electron into a proton and then into a neutron with a consequent emission of a neutrino (v).
In electron capture, the mass number of the daughter nucleus remains the same as that of the parent nucleus while the atomic number of the daughter nucleus is less than that of the parent by one unit.
A chemical formula identifies each constituent element by its chemical symbol and indicates the proportionate number of atoms of each element.
<em>For example, the empirical formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom.</em>