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Ch.2 - Atoms, Molecules & Ions
Chapter 2, Problem 102

Write symbols for the following isotopes: (a) Radon-220 (b) Polonium-210 (c) Gold-197

Verified step by step guidance
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Step 1: Understand that an isotope is represented by the chemical symbol of the element, the mass number (A), and the atomic number (Z). The format is: \( ^A_Z \text{Element} \).
Step 2: Identify the atomic number (Z) for each element using the periodic table: (a) Radon (Rn) has Z = 86, (b) Polonium (Po) has Z = 84, (c) Gold (Au) has Z = 79.
Step 3: Use the given mass numbers for each isotope: (a) Radon-220 has a mass number of 220, (b) Polonium-210 has a mass number of 210, (c) Gold-197 has a mass number of 197.
Step 4: Write the isotope symbol for each element using the format \( ^A_Z \text{Element} \): (a) \( ^{220}_{86} \text{Rn} \), (b) \( ^{210}_{84} \text{Po} \), (c) \( ^{197}_{79} \text{Au} \).
Step 5: Verify that the mass number and atomic number are correctly placed in the isotope notation for each element.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This difference in neutron count results in varying atomic masses. For example, Radon-220 has 86 protons and 134 neutrons, while Polonium-210 has 84 protons and 126 neutrons. Isotopes can be stable or radioactive, influencing their applications in fields like medicine and archaeology.
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Nuclear Notation

Nuclear notation is a way of representing isotopes using the element's symbol along with its mass number and atomic number. The mass number, which is the sum of protons and neutrons, is written as a superscript to the left of the element symbol, while the atomic number is written as a subscript. For instance, Radon-220 is denoted as ²²⁰Rn, where 220 is the mass number and 86 is the atomic number.
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Element Symbols

Element symbols are one- or two-letter abbreviations used to represent chemical elements on the periodic table. Each symbol is unique to an element and often derived from its English or Latin name. For example, Gold is represented as 'Au' from its Latin name 'Aurum'. Understanding these symbols is essential for writing chemical formulas and representing isotopes accurately.
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