Chemistry - Isotopes and Atomic Mass

What is a Isotope

• Isotopes are atoms of the same element

• they have the same protons

• but different amount of neutrons which means a different atomic mass

what is isotopic abundance

the relative amount of each isotope of an element found in a natural sample. it tells us how common each isotope is compared to the others

what is isotopic abundance used for?

its used to calculate the average atomic mass of an element on the periodic table.

what is the formula on how to calculate the average atomic mass of an element

average mass = (m1%) x (m1atomic mass) + (m2%) x (m2atomic mass)

What are radioisotopes

radioisotopes are isotopes - atoms of an element with an unstable nucleus and emit radiation as decay until they enter a more stable form

describe alpha particles

• same structure as the nucleus of a helium atom

• heavy and slow

• blocked by paper and skin

• symbol a

describe beta particles

• negatively charged electron

• lighter and faster

• passes through paper

• blocked by aluminum

• symbol b

describe gamma rays

• high energy electromagnetic radiation

• no mass

• travels at the speed of light

• blocked only by thick lead or concrete

• symbol y

what is half life

• time it takes for half of a radioactive substance to decay into a more stable form.

• a constant value for each radioisotope

• allows scientists to predict how long a radioactive material will remain active