Question

Write the abbreviated forms for the following reactions: (a) \({ }_{7}^{14} \mathrm{~N}+{ }_{2}^{4} \alpha \longrightarrow{ }_{8}^{17} \mathrm{O}+{ }_{1}^{1} \mathrm{p}\) (b) \({ }_{4}^{9} \mathrm{Be}+{ }_{2}^{4} \alpha \longrightarrow{ }_{6}^{12} \mathrm{C}+{ }_{0}^{1} \mathrm{n}\) (c) \({ }_{92}^{238} \mathrm{U}+{ }_{1}^{2} \mathrm{H} \longrightarrow{ }_{93}^{238} \mathrm{~Np}+2{ }_{0}^{1} \mathrm{n}\)

Short answer

(a) ^{14}\mathrm{N}(\alpha, \mathrm{p})^{17}\mathrm{O}, (b) ^{9}\mathrm{Be}(\alpha,\mathrm{n})^{12}\mathrm{C}, (c) ^{238}\mathrm{U}(\mathrm{d},2\mathrm{n})^{238}\mathrm{Np}.

Step-by-step solution

Understanding Reaction Notation

In the given reactions, each element is represented using isotopic notation, where the number on the top left is the atomic mass (protons + neutrons), and the number on the bottom left is the atomic number (number of protons). For example, \({ }_{7}^{14} \mathrm{~N}\) represents nitrogen with atomic number 7 and mass number 14.

Identifying Each Reaction Component

For reaction (a), identify the components: \({ }_{7}^{14} \mathrm{~N} (reactant), { }_{2}^{4} \alpha (reactant), { }_{8}^{17}\mathrm{O} (product), { }_{1}^{1} \mathrm{p} (product).\) The symbol \({ }_{2}^{4} \alpha\) is an alpha particle, \({ }_{1}^{1} \mathrm{p}\) is a proton.

Writing Abbreviated Reaction (a)

For reaction (a), combine the symbols of reactants followed by the arrow and then the symbols of the products: \[ ^{14}\mathrm{N}(\alpha, \mathrm{p})^{17}\mathrm{O}. \] The format \(A(X,Y)B\) denotes target nucleus \(A\), bombarding particle \(X\), ejected particle \(Y\), and product nucleus \(B\).

Identifying Reaction Components (b)

For reaction (b), identify the components: \({ }_{4}^{9} \mathrm{Be} (reactant), { }_{2}^{4} \alpha (reactant), { }_{6}^{12}\mathrm{~C} (product), { }_{0}^{1} \mathrm{n} (product).\) The symbol \({ }_{0}^{1} \mathrm{n}\) is a neutron.

Writing Abbreviated Reaction (b)

For reaction (b), write the abbreviated form: \[ ^{9}\mathrm{Be}(\alpha,\mathrm{n})^{12}\mathrm{C}. \] Again, following the format of target (Be), bombarding particle (alpha), ejected particle (neutron), and product (Carbon).

Identifying Reaction Components (c)

For reaction (c), identify the components: \({ }_{92}^{238} \mathrm{U} (reactant), { }_{1}^{2} \mathrm{H} (reactant), { }_{93}^{238}\mathrm{~Np} (product), 2{ }_{0}^{1} \mathrm{n} (product).\) The symbol \({ }_{1}^{2} \mathrm{H}\) is a deuterium nucleus (also hydrogen).

Writing Abbreviated Reaction (c)

For reaction (c), write the abbreviated form: \[ ^{238}\mathrm{U}(\mathrm{d},2\mathrm{n})^{238}\mathrm{Np}. \] Indicating target (Uranium), bombarding deuterium, two ejected neutrons, and resultant Neptunium.

Key concepts

Isotopic Notation

Isotopic notation is a concise way to express the identity of an atom, especially useful in nuclear reactions. In this notation, we indicate:

• The atomic number (Z): the number of protons in the nucleus, written as a subscript at the lower left of the chemical symbol.
• The mass number (A): the total number of protons and neutrons, written as a superscript at the upper left of the chemical symbol.

For instance, in the isotopic symbol \( { }_{7}^{14} \mathrm{N} \), the superscript 14 represents the mass number, and the subscript 7 is the atomic number, identifying the element as nitrogen. This helps in keeping track of nuclear reactions as the mass number is conserved while protons, neutrons, or other particles rearrange or convert into each other.

Alpha Particle

An alpha particle is a type of nuclear particle consisting of two protons and two neutrons, and it is equivalent to a helium nucleus. Represented by the notation \( { }_{2}^{4} \alpha \), the subscript 2 indicates the two protons, while the superscript 4 is the mass number (the total of protons and neutrons).Alpha particles have a positive charge and are relatively large compared to other particles like beta particles. In nuclear reactions, alpha particles often act as bombarding particles. For instance, when \( { }_{2}^{4} \alpha \) collides with \( { }_{7}^{14} \mathrm{~N} \), a nuclear reaction occurs, producing oxygen \( { }_{8}^{17} \mathrm{O} \) and a proton \( { }_{1}^{1} \mathrm{p} \).

• The mass and charge of an alpha particle cause it to be strongly ionizing, meaning it can easily remove electrons from atoms.
• Due to its size, it has relatively low penetration power and can be stopped by a sheet of paper or human skin.

Neutron

A neutron is a neutral particle, meaning it has no charge, found in the nucleus of an atom. Its symbol is \( { }_{0}^{1} \mathrm{n} \), where the subscript 0 denotes its lack of charge, and the superscript 1 indicates its rough mass equivalence to a proton (or atomic mass unit).Neutrons play a crucial role in nuclear reactions, especially because they can penetrate other nuclei without being repelled electrically (unlike protons and other charged particles). In a reaction like \( { }_{4}^{9} \mathrm{Be} + { }_{2}^{4} \alpha \rightarrow { }_{6}^{12} \mathrm{C} + { }_{0}^{1} \mathrm{n} \), an alpha particle strikes beryllium, resulting in carbon and the ejection of a neutron.

• Neutrons can initiate nuclear reactions upon colliding with other nuclei, leading to the formation of different elements or isotopes.
• The presence and arrangement of neutrons in the nucleus influence the stability of atoms and the isotopic form they take.