In an alpha decay, the original nucleus decays into a daughter nucleus + an alpha particle, which consists of 2 protons and 2 neutrons.
The atomic number (number of protons) of the Francium is 87, and since in the decay it loses 2 protons, the atomic number of the daughter nucleus should be 85. Looking at the periodic table ,this corresponds to Astatine, and therefore this is the element produced in the alpha decay of Francium-221.
Moreover, the mass number (number of protons+neutrons) decreases by 4 (because an alpha particle carries 2 protons+2 neutrons), therefore in the reaction the mass number will decrease from 221 to 217.
So, the daughter element is astatine-217.
The correct answer is (a.) The rider uses energy to do work going up the mountain. As the law of conservation of energy states that the total energy must be constant, therefore, the energy that is used to go up will be as it is to go down.
Force = mass * acceleration
15 = 2.1 * a
a = 15/2.1 = 7.143 m/s^2
Once the virus gets into the host's body, it enters the nearest cell.Once it gets to the nucleus it turns that cell into a virus-production cell and once the immune system detects those viruses it takes action.
