Argon has three naturally occurring isotopes, with mass numbers 36, 38, and 40.
a. Write the atomic symbol for each of these atoms.

Verified step by step guidance

1. Step 1: Recall the general format for writing an atomic symbol. The atomic symbol is written as \( ^{A}_{Z}X \), where \( A \) is the mass number (number of protons + neutrons), \( Z \) is the atomic number (number of protons), and \( X \) is the chemical symbol of the element.
2. Step 2: Identify the chemical symbol for argon. The chemical symbol for argon is 'Ar', and its atomic number \( Z \) is 18 (since argon has 18 protons).
3. Step 3: Write the atomic symbol for the isotope with a mass number of 36. Using the format \( ^{A}_{Z}X \), this isotope is written as \( ^{36}_{18}Ar \).
4. Step 4: Write the atomic symbol for the isotope with a mass number of 38. Similarly, this isotope is written as \( ^{38}_{18}Ar \).
5. Step 5: Write the atomic symbol for the isotope with a mass number of 40. Following the same format, this isotope is written as \( ^{40}_{18}Ar \).

Key Concepts

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers. For example, argon has three isotopes: argon-36, argon-38, and argon-40, which correspond to the mass numbers 36, 38, and 40, respectively.

Atomic Symbol

The atomic symbol is a notation that represents a chemical element, consisting of one or two letters derived from its name, often accompanied by the mass number. For argon, the atomic symbol is 'Ar', and when denoting its isotopes, it is written as Ar-36, Ar-38, and Ar-40, indicating the specific mass number of each isotope.

Mass Number

The mass number of an atom is the total count of protons and neutrons in its nucleus. It is crucial for identifying isotopes, as different isotopes of the same element will have varying mass numbers due to differing neutron counts. In the case of argon, the mass numbers 36, 38, and 40 reflect the different isotopes of the element.