Question #575fe

1 Answer
Jun 23, 2016

""_ (color(white)(a)47)^113"Ag" -> ""_ (color(white)(a)48)^113"Cd" + ""_ (-1)^(color(white)(aa)0)beta + bar(nu)_"e"113a47Ag113a48Cd+aa01β+¯νe

Explanation:

Your strategy here will be to use the fact that in a nuclear reaction, mass and charge are conserved.

In your case, the nuclear reaction involves the decay of silver-113 to cadmium-113

""_ (color(white)(a)47)^113"Ag" -> ""_ (color(white)(a)48)^113"Cd" + ""_color(red)(x)^color(blue)(y)?113a47Ag113a48Cd+yx?

Your goal now is to find the values of color(red)(x)x and color(blue)(y)y. You can write

113 = 113 + color(blue)(y) ->113=113+y conservation of mass

color(white)(a)47 = color(white)(a)48 + color(red)(x) ->a47=a48+x conservation of charge

This gets you

113 = 113 + color(blue)(y) implies color(blue)(y) = 0113=113+yy=0

and

47 = 48 + color(red)(x) implies color(red)(x) = 47 - 48 = -147=48+xx=4748=1

Therefore, your unknown particle has a mass number of 00 and a charge of 1-1. At this point, you should recognize that your unknown particle is a high-speed electron, also called beta particle, ""_(-1)^(color(white)(aa)0)betaaa01β.

The nuclear equation given to you describes the beta minus decay of silver-113.

""_ (color(white)(a)47)^113"Ag" -> ""_ (color(white)(a)48)^113"Cd" + ""_(-1)^(color(white)(aa)0)beta113a47Ag113a48Cd+aa01β

It's worth mentioning that beta minus decay also produces an electron antineutrino, bar(nu)_"e"¯νe, so the complete nuclear equation would look like this

color(green)(|bar(ul(color(white)(a/a)color(black)(""_ (color(white)(a)47)^113"Ag" -> ""_ (color(white)(a)48)^113"Cd" + ""_ (-1)^(color(white)(aa)0)beta + bar(nu)_"e")color(white)(a/a)|)))

As you can see, in beta minus decay, a neutron is converted into a proton and an electron and an antineutrino are emitted from the nucleus.

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