Question

Write down equations to describe the alpha decay of the following atoms: a) \(^{212} \mathrm{Rn}\) b) \({ }^{241} \mathrm{Am}\)

Short answer

Question: Identify the daughter atoms and write the equations for the alpha decays of the following parent atoms: a) \(^{212}\mathrm{Rn}\) and b) \(^{241}\mathrm{Am}\). Answer: The daughter atoms are: a) \(^{208}\mathrm{Po}\) (Polonium) b) \(^{237}\mathrm{Np}\) (Neptunium) The equations for the alpha decays are: a) \(^{212}\mathrm{Rn} \rightarrow \, ^{208}\mathrm{Po} + ^4\mathrm{He}\) b) \(^{241}\mathrm{Am} \rightarrow \, ^{237}\mathrm{Np} + ^4\mathrm{He}\)

Step-by-step solution

Identify the alpha particle

An alpha particle is a helium-4 nucleus, which consists of 2 protons and 2 neutrons. Therefore, the alpha particle can be represented as \(^4\mathrm{He}\).

Write down the initial parent atoms

The given parent atoms are: a) \(^{212}\mathrm{Rn}\) b) \(^{241}\mathrm{Am}\)

Determine the daughter atoms after the alpha decay

When a parent atom undergoes alpha decay, it loses 2 protons and 2 neutrons (which are contained in the alpha particle). Therefore, the atomic number (Z) of the daughter atom will be 2 less than the parent atom, and the mass number (A) will be 4 less than the parent atom. a) For \(^{212}\mathrm{Rn}\) (Rn has an atomic number of 86): Daughter atom will have an atomic number of 86 - 2 = 84 Daughter atom will have a mass number of 212 - 4 = 208 So, the daughter atom will be \(^{208}\mathrm{Po}\) (Polonium). b) For \(^{241}\mathrm{Am}\) (Am has an atomic number of 95): Daughter atom will have an atomic number of 95 - 2 = 93 Daughter atom will have a mass number of 241 - 4 = 237 So, the daughter atom will be \(^{237}\mathrm{Np}\) (Neptunium).

Write the equations for the alpha decays of the given atoms

Finally, we can write down the equations for the alpha decays: a) \(^{212}\mathrm{Rn} \rightarrow \, ^{208}\mathrm{Po} + ^4\mathrm{He}\) b) \(^{241}\mathrm{Am} \rightarrow \, ^{237}\mathrm{Np} + ^4\mathrm{He}\)

Key concepts

Radioactive Decay

Radioactive decay is a natural process where unstable atomic nuclei lose energy. This happens in different ways, but one of the most common is alpha decay. During alpha decay, an atom emits an alpha particle. This helps the atom move towards a more stable state.
Alpha decay typically occurs in very heavy elements, which often have too many protons to be stable. These elements include uranium, radon, and americium.
In general, the emission leads to a significant change in the atom. The original atom, known as the parent atom, loses an alpha particle and becomes a daughter atom. The alpha particle consists of two protons and two neutrons (the same as a helium nucleus).

Nuclear Equations

Nuclear equations help us understand what happens during radioactive decay. They have a specific format, similar to chemical equations. They show the transformation from the parent atom to the daughter atom, with the release of an alpha particle.
Here's what makes a nuclear equation:

• The parent nuclide symbolizes the starting atom. Its mass number is written at the top left, and its atomic number is at the lower left.
• The daughter nuclide follows the same pattern, showing the new atom after decay.
• The alpha particle, represented as \(^{4}\mathrm{He}\), is on the right side of the equation.

By balancing the equation, we ensure that the mass number and atomic number are consistent on both sides, reflecting the conservation of mass and charge.

Helium Nucleus

The helium nucleus, also known as an alpha particle, plays a crucial role in alpha decay. It consists of two protons and two neutrons. This small piece of an atom gives off energy as the atom decays.
Helium nuclei are quite stable, which is why they are one of the preferred emissions in decay processes. They help the unstable parent atom reach a more balanced state.

• The two protons give the helium nucleus a charge of +2.
• Due to its mass and charge, the alpha particle doesn't travel far. It can be blocked by materials as thin as paper.
• After emission, the alpha particle slows down, often gaining electrons and turning into a helium atom.

Understanding this helps us see how alpha decay transforms more unstable atoms into stable ones.

Parent and Daughter Atoms

In the world of radioactive decay, the transformation of a parent atom into a daughter atom is fundamental. The parent atom is the original unstable atom that undergoes decay. After losing an alpha particle, it becomes the daughter atom, a new element.
The attributes of these atoms change in alpha decay:

• The atomic number (number of protons) decreases by 2. This means a change in the element itself since elements are defined by their proton numbers.
• The mass number (total of protons and neutrons) decreases by 4. This loss accounts for the mass of the alpha particle.

In this process, the parent atom often transforms into a different element, helping students understand the basics of nuclear chemistry.