Question #4a5cf

1 Answer
Dec 28, 2016

Answer:

Alpha radiation.

Explanation:

Polonium-212 undergoes alpha decay to produce lead-208, which means that it gives off alpha radiation, i.e. alpha particles.

An alpha particle, #alpha#, is simply the nucleus of a helium-4 atom, which means that it contains

  • two protons
  • two neutrons

https://www.mirion.com/introduction-to-radiation-safety/types-of-ionizing-radiation/

When a radioactive nuclide emits an alpha particle

  • its mass number will decrease by #4#

The mass number, #A#, is given by the number of protons and neutrons, and so

#A = "2 protons " + " 2 neutrons" = 4#

  • its atomic number will decrease by #2#

The atomic number, #Z#, is given by the number of protons, and so

#Z = "2 protons" = 2#

Now, the two elements that you're working here with have

#"Po: " {(A = 212),(Z = 84) :}" "# and #" " "Pb: " {(A = 208), (Z = 82) :}#

This confirms that you're dealing with an alpha decay because the balanced nuclear equation that describes this process looks like this

#""_ (color(white)(1)color(darkgreen)(84))^color(blue)(212)"Po" -> ""_ (color(white)(1)color(darkgreen)(82))^color(blue)(208)"Pb" + ""_ color(darkgreen)(2)^color(blue)(4)alpha#

Notice that mass and charge are conserved, since

#color(blue)(212 = 208 + 4) -># conservation of mass

#color(darkgreen)(84 = 82 + 2) -># conservation of charge