Predicting

Table of radioactive isotopes below

Isotope type of decay
Uranium-238 Alpha
Nickel-63 Beta
Iodine-131 Beta
Radium-226 Alpha

With the help of a periodic table, predict the element that forms in each case. Explain your reasoning.

To predict the element formed in each case, we need to understand the decay processes involved and the elements involved in the decay series.

1. Uranium-238 (α-decay):
During α-decay, an alpha particle (which consists of two protons and two neutrons) is emitted from the nucleus. This leads to a decrease in the atomic number by 2 and the mass number by 4.

Since uranium-238 decays via alpha decay, the resulting element can be determined by subtracting 2 from the atomic number of uranium (U). Therefore, the element that forms after alpha decay is Thorium (Th).

2. Nickel-63 (β-decay):
During β-decay, a neutron within the nucleus is converted into a proton, and an electron, called a beta particle, is released. This leads to an increase in the atomic number by 1.

Nickel-63 undergoes beta decay, where a neutron is converted into a proton. Therefore, the element that forms after beta decay is Copper (Cu).

3. Iodine-131 (β-decay):
Similar to Nickel-63, during β-decay, a neutron within the iodine-131 nucleus is converted into a proton, and an electron (beta particle) is released.

Iodine-131 undergoes beta decay, which means a neutron is converted into a proton. Therefore, the element that forms after beta decay is Xenon (Xe).

4. Radium-226 (α-decay):
Again, during α-decay, an alpha particle is emitted from the nucleus, leading to a decrease in the atomic number by 2 and the mass number by 4.

Radium-226 decays via alpha decay, so the resulting element can be determined by subtracting 2 from the atomic number of radium (Ra). Therefore, the element formed after alpha decay is Radon (Rn).

So, based on the type of decay and the change in atomic numbers, the elements formed from each radioactive isotope are as follows:
- Uranium-238 → Thorium (Th)
- Nickel-63 → Copper (Cu)
- Iodine-131 → Xenon (Xe)
- Radium-226 → Radon (Rn)

To predict the element that forms in each case, we need to understand how isotopes decay and how they transform into new elements.

1. Uranium-238 undergoes alpha decay. In alpha decay, an alpha particle (which consists of two protons and two neutrons) is emitted. Since uranium-238 has 92 protons, the emission of an alpha particle removes two protons, resulting in an element with an atomic number of 90. Referring to the periodic table, we can see that the element with atomic number 90 is thorium (Th).

2. Nickel-63 undergoes beta decay. In beta decay, a neutron inside the nucleus is converted into a proton and emits a beta particle (which is an electron). This increases the atomic number by one. Nickel-63 has 28 protons, so the conversion of a neutron into a proton results in an atomic number of 29. Referring to the periodic table, we can see that the element with atomic number 29 is copper (Cu).

3. Iodine-131 also undergoes beta decay. Similar to the previous case, a neutron is converted into a proton and emits a beta particle. Iodine-131 has an atomic number of 53, so converting one neutron into a proton increases the atomic number to 54. Referring to the periodic table, the element with atomic number 54 is xenon (Xe).

4. Radium-226 undergoes alpha decay. Just like uranium-238, the emission of an alpha particle removes two protons from the nucleus. Radium-226 has 88 protons, so removing two protons results in an atomic number of 86. Referring to the periodic table, the element with atomic number 86 is radon (Rn).

By understanding the process of alpha and beta decay and referring to the periodic table for atomic numbers, we can predict the elements that form in each case.