How is it possible that certain elements can change into other elements?

e x / atoms of carbon can become atoms of nitrogen

Radioactive Decay: process where atomic nuclei of radioactive isotopes release fast-moving particles and energy

during radioactive decay, the identity of an atom changes

radioactive decay is an example of a nuclear reaction

Nuclear Reactions: involve the particles in the nucleus of an atom

ex/ Nuclear Fission: process in which atomic nuclei split apart

ex/ Nuclear Fusion: process in which atomic nuclei join together

both examples of a nuclear reaction

These physical processes make it possible for scientists to turn one element into another

1896- French scientist Henri Becquerel accidentally discovered the effects of Radioactive Decay

Radioactivity: when an element (uranium) spontaneously emits radiation, named by Marie Curie, worked on by Marie Curie, her husband chemist Pierre Curie, and Becquerel who presented his findings to the Curie’s

All three were awarded Nobel Prize in Physics

Marie had another one later for her research in Radioactive Elements. She died of cancer, as a result of exposure to radium.

Alpha Particle: consists of two protons + two neutrons; positively charged

the release of this particle during alpha decay decreases the atomic number by two and the mass number by 4

Beta Particle: fast-moving electron given off by a nucleus during radioactive decay. A new proton remains inside the nucleus, nucleus is then left w/ one less neutron + one more proton. Mass # stays the same, but its atomic # increases by 1

during beta decay, a neutron in an unstable nucleus changes into a negatively charged beta particle + a proton

Gamma Rays(also known as gamma radiation): consist of high-energy waves, similar to x-rays. They have no charge + do not cause a change in either the atomic mass or the atomic #

Alpha + Beta decay are almost always accompanied by gamma radiation

Uses of Radioactive isotopes: determining the ages of fossils, tracing the steps of a chemical reaction and industrial processes, diagnosing and treating disease, and providing sources of energy

Half-life: (of a radioactive substance) the length of time needed for half of the atoms of a sample to decay, different for each radioactive isotope (can range from less than a second to billions of years)

Radioactive Dating: when scientists measure the amount of carbon-14 in a preserved fossil to calculate how many half-lives have passed since it died and estimate the age

Tracers: radioactive isotopes that can be followed through the steps of a chemical reaction or an industrial process. They behave chemically like nonradioactive forms of an element