Question

Write isotopic symbols in the form \(\mathrm{X}-A(\) e.g. \(, \mathrm{C}-13)\) for each isotope. \begin{equation} \begin{array}{l}{\text { a. the silver isotope with } 60 \text { neutrons }} \\\ {\text { b. the silver isotope with } 62 \text { neutrons }} \\ {\text { c. the uranium isotope with } 146 \text { neutrons }} \\ {\text { d. the hydrogen isotope with } 1 \text { neutron }}\end{array} \end{equation}

Short answer

a. \(\mathrm{Ag}-107\), b. \(\mathrm{Ag}-109\), c. \(\mathrm{U}-238\), d. \(\mathrm{H}-2\) (Deuterium)

Step-by-step solution

Identify the Atomic Number of Silver

Look up the atomic number of silver (Ag) on the periodic table. The atomic number, which is the number of protons in the nucleus of an atom, is unique to each element. For silver, the atomic number is 47.

Calculate the Mass Number for Silver Isotopes

To find the mass number (A) of each silver isotope, add the number of neutrons given in the problem to the atomic number of silver (number of protons). For silver isotope with 60 neutrons: Mass Number (A) = Atomic Number (47) + Number of Neutrons (60) = 107. For silver isotope with 62 neutrons: Mass Number (A) = Atomic Number (47) + Number of Neutrons (62) = 109.

Identify the Atomic Number of Uranium

Look up the atomic number of uranium (U) on the periodic table. The atomic number of uranium is 92.

Calculate the Mass Number for the Uranium Isotope

Calculate the mass number of the uranium isotope with 146 neutrons: Mass Number (A) = Atomic Number (92) + Number of Neutrons (146) = 238.

Identify the Atomic Number of Hydrogen

Find the atomic number of hydrogen (H) on the periodic table. The atomic number of hydrogen is 1, which is also the number of protons in hydrogen.

Calculate the Mass Number for the Hydrogen Isotope

Calculate the mass number of the hydrogen isotope with 1 neutron: Mass Number (A) = Atomic Number (1) + Number of Neutrons (1) = 2.

Write the Isotopic Symbols

Write the isotopic symbols using the format \(\mathrm{X}-A\) where X is the chemical symbol and A is the mass number. For the given isotopes: - The silver isotope with 60 neutrons is \(\mathrm{Ag}-107\). - The silver isotope with 62 neutrons is \(\mathrm{Ag}-109\). - The uranium isotope with 146 neutrons is \(\mathrm{U}-238\). - The hydrogen isotope with 1 neutron is \(\mathrm{H}-2\), also known as Deuterium.

Key concepts

Atomic Number

The atomic number is a fundamental characteristic of each chemical element, representing the number of protons found in the nucleus of an atom. It is denoted by the symbol 'Z'. This number is crucial because it defines the element: for example, all atoms with an atomic number of 1 are hydrogen atoms, and those with an atomic number of 47 are silver atoms. Since protons are positively charged, the atomic number also tells us about the charge of the nucleus and the number of electrons in a neutral atom.

When looking up an element on the periodic table, the atomic number is usually found above the symbol of the element. It helps in identifying the element and is the primary basis for the organization of the periodic table.

Mass Number

The mass number, represented by 'A', is the total number of protons and neutrons in an atom's nucleus. Unlike the atomic number, the mass number is not constant for a given element because the number of neutrons can vary. These variations lead to different isotopes of an element. For example, silver (Ag) with a mass number of 107 has 60 neutrons, while silver with a mass number of 109 has 62 neutrons.

To calculate the mass number, you simply add the number of protons (the atomic number) to the number of neutrons. It is important to understand that the mass number is a whole number and represents the 'bulk' of the atom's mass since protons and neutrons are significantly heavier than electrons.

Neutrons

Neutrons are one of the three main particles that make up an atom, along with protons and electrons. Neutrons are located in the nucleus and have a neutral charge, which means they neither attract nor repel electrons or other neutrons. The number of neutrons in the nucleus can greatly affect the physical properties of an atom, including its stability and the way it interacts with other atoms.

In the context of isotopes, the number of neutrons is what distinguishes one isotope from another. While isotopes of an element have the same atomic number (and thus the same number of protons and electrons), they differ in their neutron count, which leads to differences in their mass numbers.

Chemical Elements

Chemical elements are pure substances that consist of only one type of atom, distinguished by their atomic number. They serve as the building blocks for all matter in the universe. The known elements are systematically arranged in the periodic table, which groups them based on shared properties and their atomic numbers. Elements can combine with each other to form compounds through chemical reactions.

Understanding elements involves more than just knowing their names and symbols. It requires familiarity with their properties, such as atomic and mass numbers, and how these can vary in isotopes. Each element can have several isotopes, which are atoms with the same number of protons but different numbers of neutrons. These isotopes can be stable or unstable (radioactive), and studying them helps us to understand the complexity of the atomic world and its applications in various fields such as medicine, archaeology, and energy production.