When Bismuth-211 decays by emitting an alpha particle, a helium molecule is released together with the new element.
for alpha particle 4He2
4 = mass number
2 = atomic number
Bismuth has an atomic number of 83 therefore the new element produced shoud have a mass number of 207 and atomic number of 81.
This corresponds to approximately 207 Tl 81
Answer:
It matters
Explanation:
Pure substance are known to have a sharp freezing point. However, the presence of solute lowers the freezing point of the solvent. The best time to measure the freezing point is when the freezing process is just beginning.
It will be an error to measure the freezing point when the part of the solution has already frozen.
Answer:
The analogy that best describes is "The planets go around the sun."
Explanation:
The best analogy that suggests that electrons moves round the nucleus in an atom is the Bohr model. According to Neil Bohr, Based on Rutherford's model, he suggested that the extra nuclear part consists of electrons.
These electrons are in the spherical orbits called shells or energy levels around the nucleus.
The nucleus is the tiny massive center of the atom.
Transition of electrons takes place from one level to another.
The temperature changes in the water and climate up willing all the fish to go away from the surface