Polonium has a mass number of 212 and an atomic number of 84, In balanced nuclear reaction, polonium releases an alpha particle to produce lead. Which option is the atomic number of lead?
A. 82
B. 208
C. 80
D. 210
The atomic number of an element is the same as the number of protons it has. In this case, polonium has an atomic number of 84. When it releases an alpha particle, it loses 2 protons, so the resulting element, lead, must have an atomic number that is 2 less than 84.
Therefore, the correct option is A. 82
Polonium has an atomic number of 84, which means it has 84 protons in its nucleus. When it undergoes alpha decay, it releases an alpha particle, which consists of 2 protons and 2 neutrons.
Since the atomic number of polonium is 84, the atomic number of the resulting element, lead, can be found by subtracting 2 (the number of protons in the alpha particle) from 84.
Therefore, the atomic number of lead is 84 - 2 = 82.
So the correct option is A. 82.
To determine the atomic number of lead (Pb), we need to understand the process of alpha decay and the relationship between atomic numbers and mass numbers.
In alpha decay, an alpha particle (consisting of two protons and two neutrons) is emitted from the nucleus. This results in a new element with an atomic number that is two units lower and a mass number that is four units lower than the original element.
In this case, polonium (Po) undergoes alpha decay to produce lead (Pb). Polonium has an atomic number of 84 and a mass number of 212. When an alpha particle (two protons and two neutrons) is emitted, the atomic number decreases by 2 and the mass number decreases by 4.
Therefore, the atomic number of lead can be determined by subtracting 2 from the atomic number of polonium:
84 - 2 = 82
So, the correct option is A. 82.