Question

True or false? Radioactive decay ends up changing the elemental identity of the isotope undergoing decay. Explain.

Short answer

True. Radioactive decay changes the elemental identity of the isotope undergoing decay, as it involves a change in the number of protons within the atomic nucleus, affecting the atomic number and the elemental identity. Examples include alpha decay, which decreases the atomic number by 2, and beta decay, which increases the atomic number by 1.

Step-by-step solution

Understand radioactive decay

Radioactive decay is a process in which an unstable atomic nucleus loses energy by emitting radiation, such as alpha particles, beta particles, or gamma rays. This process leads to the formation of a new atom with a different number of protons and neutrons than the original atomic nucleus.

Determine the effect on the elemental identity

The elemental identity of an atom is determined by the number of protons present in its nucleus, which is also known as the atomic number. During radioactive decay, the atomic nucleus undergoes a transformation that may cause a change in the number of protons. For instance, in alpha decay, the nucleus emits an alpha particle which consists of 2 protons and 2 neutrons, resulting in a decrease in the atomic number of the original nucleus by 2. In beta decay, a neutron in the nucleus is converted into a proton, increasing the atomic number of the original nucleus by 1.

Conclude if the statement is true or false

Since radioactive decay involves a change in the number of protons within the atomic nucleus, which affects the atomic number and thus the elemental identity, we can conclude that the statement is true. Radioactive decay does end up changing the elemental identity of the isotope undergoing decay.

Key concepts

Atomic Nucleus

An atomic nucleus is the heart of an atom. This tiny, dense region at the center of an atom contains protons and neutrons, also known as nucleons. The nucleus is held together by a fundamental force called the strong nuclear force.
- **Protons:** These are positively charged particles. The number of protons in a nucleus determines the element to which the atom belongs. This number is known as the atomic number. - **Neutrons:** These particles have no electrical charge. They add mass to the atom and participate in nuclear reactions. While protons and neutrons together define the mass of the atom, it's primarily the number of protons that determines its elemental identity. In radioactive decay processes, changes in the nucleus lead to the creation of new elements.

Alpha Decay

Alpha decay is a type of radioactive decay where an unstable nucleus ejects an alpha particle. An alpha particle consists of 2 protons and 2 neutrons, essentially a helium-4 nucleus.
When an atom undergoes alpha decay: - The atomic number decreases by 2, because it loses 2 protons. - The atomic mass decreases by 4 due to the loss of both protons and neutrons. This transformation alters the original element's identity. For example, if uranium-238 undergoes alpha decay, it will transform into thorium-234. This is because the loss of 2 protons causes a change in the element itself.

Beta Decay

Beta decay occurs in two forms: beta-minus and beta-plus decay. It involves the transformation of neutrons and protons within the nucleus and leads to a change in the atomic number.
- **Beta-minus decay:** A neutron is converted into a proton, and an electron, known as a beta particle, is emitted. As a result: - The atomic number increases by 1, as the neutron becomes a proton. - The atomic mass remains relatively unchanged since protons and neutrons have nearly the same mass. - **Beta-plus decay (positron emission):** Here, a proton is converted into a neutron, and a positron is emitted. As a result: - The atomic number decreases by 1. Both types of beta decay result in a change in the elemental identity of the atom due to a change in the proton count.

Elemental Identity

The elemental identity of an atom is defined by its atomic number, which represents the number of protons in its nucleus. Each element on the periodic table has a unique atomic number, and thus a distinct elemental identity.
When the number of protons in a nucleus changes, the atom's elemental identity changes. This is exactly what happens during radioactive decay processes like alpha and beta decay. - **Alpha decay:** Reduces the atomic number by 2, resulting in a shift to a new element. - **Beta decay:** Increases or decreases the atomic number by 1, depending on the type of beta decay. Therefore, radioactive decay can fundamentally alter the identity of an atom, transforming it into a different element altogether. Recognizing this shift is crucial for understanding how elements transform in nature.