# Isotopes, atomic mass, abundance

• CMATT
In summary, isotopes are atoms of the same element with different numbers of neutrons, resulting in a difference in atomic mass while maintaining the same chemical properties. Atomic mass is the average mass of all isotopes of an element, taking into account their relative abundance. This is calculated by multiplying the mass of each isotope by its relative abundance and adding them together. Relative abundance is the percentage of each isotope compared to the total amount of that element, and it is important to consider isotopes and their abundance because they impact the atomic mass and therefore the chemical and physical properties of elements. This information is also crucial in various fields such as nuclear energy, environmental science, and archaeology.

## Homework Statement

Suppose the element A contains three isotopes, 86A (atomic mass 85.909 u, abundance 16.19%) 87A (atomic mass 86.908, abundance 7.00%) and 88A (atomic mass 87.906 u). What would be the atomic mass of A that would appear in the periodic table?

## Homework Equations

(A1 x %A1) + (A2 x %A2) + (A3 x (1-(%1 +%2)) = answer

## The Attempt at a Solution

16.19% + 7.00% = 23.19%

100% - 23.19% = 76.81% --> so that would be the 88A abundance % right?

CMATT said:
100% - 23.19% = 76.81% --> so that would be the 88A abundance % right?
Sure.
CMATT said:
Just plug everything into the equation you have.

## What are isotopes?

Isotopes are atoms of the same element that have different numbers of neutrons. This results in a difference in the atomic mass, but the chemical properties of the element remain the same.

## What is atomic mass?

Atomic mass is the average mass of all the isotopes of an element, taking into account their relative abundance.

## How is atomic mass calculated?

Atomic mass is calculated by multiplying the mass of each isotope by its relative abundance and then adding all of these values together.

## What is relative abundance?

Relative abundance is the percentage of each isotope that exists in nature compared to the total amount of that element. It is usually expressed as a decimal or percentage.

## Why is it important to consider isotopes and their abundance?

Isotopes and their abundance are important because they affect the atomic mass of elements, which in turn affects their chemical and physical properties. This information is also crucial in fields such as nuclear energy, environmental science, and archaeology.