If the following element undergoes alpha decay, which element does it change into?
234/90Th
a
Uranium (U)
b
Francium (Fr)
c
Radium (Ra)
d
Radon (Rn)
The correct answer is c) Radium (Ra).
If the element with the atomic number 90 (which corresponds to the element thorium, symbol Th) undergoes alpha decay, it will change into an element with an atomic number that is decreased by 2 and an atomic mass that is decreased by 4.
Therefore, the correct answer is:
c) Radium (Ra)
To determine which element the given element changes into during alpha decay, we need to first understand what alpha decay is.
Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle. An alpha particle consists of two protons and two neutrons, which is essentially a helium-4 nucleus. During alpha decay, the atomic number of the element decreases by 2 and the mass number decreases by 4.
In the given element, 234/90Th (Thorium), if it undergoes alpha decay, it will emit an alpha particle and change into a new element.
To find the new element, we subtract 2 from the atomic number (90 - 2 = 88) and subtract 4 from the mass number (234 - 4 = 230). This gives us the new element with atomic number 88 and mass number 230.
The element with atomic number 88 is Radium (Ra). Therefore, the correct answer is c) Radium (Ra).