Answer Gold Beta & Alpha Decay Questions

In summary, the daughter nucleus after a gold nucleus (Au) undergoes beta decay is mercury (Hg). If the gold nucleus had undergone alpha decay instead, the daughter nucleus would be iridium (Ir). Beta decay results in no change in mass and an increase of one in atomic number, while alpha decay results in a loss of four atomic mass units and two atomic number units.
  • #1
kirsten_2009
137
2

Homework Statement



Use the periodic table to find the daughter nucleus after a gold nucleus (Au) undergoes beta decay. What would be the result if the gold nucleus had undergone alpha decay instead?

Homework Equations

The Attempt at a Solution




Beta Decay: A=196.96655 Z=80 Au

Alpha Decay: A=192 Z=77 Ir

I have a couple of questions regarding radioactive decay...is it accurate to say that all beta decays for all radioactive elements results in the loss of a neutron and the gain of a proton? So, the element's atomic number increases by 1 but the mass number stays the same? Also, then is it accurate to say that all alpha decay for all elements results in 2 neutrons being loss and 2 protons being loss? So, all alpha decay results in another element different from the starting one? but beta stays the same element? Sorry for all the questions...I'm just not sure I get it. Thanks!


 
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  • #2
kirsten_2009 said:

Homework Statement



Use the periodic table to find the daughter nucleus after a gold nucleus (Au) undergoes beta decay. What would be the result if the gold nucleus had undergone alpha decay instead?

Homework Equations

The Attempt at a Solution

Beta Decay: A=196.96655 Z=80 Au

Alpha Decay: A=192 Z=77 Ir

I have a couple of questions regarding radioactive decay...is it accurate to say that all beta decays for all radioactive elements results in the loss of a neutron and the gain of a proton? So, the element's atomic number increases by 1 but the mass number stays the same? Also, then is it accurate to say that all alpha decay for all elements results in 2 neutrons being loss and 2 protons being loss? So, all alpha decay results in another element different from the starting one? but beta stays the same element? Sorry for all the questions...I'm just not sure I get it. Thanks!

You get it --- elements are identified by atomic number, not mass.
 
  • #3
O.k thank-you...so my answer is correct then? Should I round to 197 for Au's mass number?
 
  • #4
You said, "Z=80." Which element in the periodic table is identified by Z=80?
 
  • #5
Mercury but it's mass number is not the same as Gold's...? Is this like some "special mercury" that comes from radioactive gold?
 
  • #6
Had to check a table of isotopes --- Au197 is a "stable" isotope, and its natural abundance is 100% (all naturally occurring gold is 197). Hg197 is an unstable isotope of mercury that decays back to gold by electron capture with a half life around 4 days. You are being taught from a really weird textbook.

They gave you definitions for α and β decay processes: restating them for you, α decay results in a loss of four atomic mass units and two atomic number units; β decay results in no change in mass and an increase of one in atomic number.

The exercise is just intended to get you used to how to skip backward or forward in the periodic table for the two decay processes without regard to whether the specific decays actually occur in nature.

kirsten_2009 said:
Is this like some "special mercury"

It's an isotope --- the teaching materials you're working from may present you with isotopes that don't even exist given that they've already asked you to look at alpha and beta decays of Au197. Iridium and mercury, and neither decay process actually occurs.

The odd numbers you see for atomic mass (196.______) are averages of the isotopic masses x abundances of those masses in a sample of a particular element, so don't let them throw you.
 
  • #7
Thanks for the help! So really my answer should be...

Beta Decay: A=197 Z=80 Hg

Alpha Decay: A=193 Z=77 Ir
 
  • #8
Yup.
 

What is the difference between beta and alpha decay?

Beta decay is the process in which a nucleus releases a beta particle (an electron or positron) in order to become more stable. Alpha decay is the process in which a nucleus releases an alpha particle (two protons and two neutrons) in order to become more stable. In beta decay, the nucleus changes to a different element, while in alpha decay, the element remains the same but with a smaller atomic mass.

How is the rate of decay determined?

The rate of decay is determined by the half-life, which is the amount of time it takes for half of the atoms in a sample to decay. This rate is constant for a specific isotope, meaning that after one half-life, half of the sample will have decayed, after two half-lives, three-fourths will have decayed, and so on.

What is the significance of beta and alpha decay in nuclear reactions?

Beta and alpha decay play important roles in nuclear reactions by balancing the number of protons and neutrons in a nucleus. When a nucleus is unstable due to having too many or too few of these particles, it can undergo beta or alpha decay to achieve a more stable configuration.

What is the difference between radioactive and stable nuclei?

Radioactive nuclei are unstable and will undergo decay to become more stable. They have an excess of energy and particles, which they release through decay. Stable nuclei, on the other hand, do not undergo decay and have a balanced number of protons and neutrons in their nucleus.

How does the energy released in alpha and beta decay compare?

The energy released in alpha decay is typically much larger than that released in beta decay. This is because alpha particles have a higher mass and therefore carry more energy when they are released from a nucleus. However, the amount of energy released in beta decay can vary depending on the type of beta particle (electron or positron) and the specific isotope undergoing decay.

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