Radioactivity

Question 1

Radioactivity

Answer 1

is the spontaneous breaking up of unstable nuclei with the emission of one or more types of radiation

Question 2

Alpha particles

Answer 2

-2 protons and 2 neutrons
-the nucleus of a Helium atom
-positive charge
-weak: stopped by paper
E.g Americium-241 - smoke detectors

Question 3

Beta particles

Answer 3

-quickly moving electron
-a neutron in the nucleus of the element turns into a proton and an electron, the proton stays in the nucleus but the electron is shot off out of the nucleus
-negative charge
-medium:stopped by 4mm of Al
-E.g Carbon-14 - radiocarbon dating

Question 4

Gamma radiation

Answer 4

-a strong form of electromagnetic radiation
-travels at light speed
-extremely dangerous : high energy and speed
-no changes to the number of protons or neutrons in the nucleus
-no charge
-strong: stopped by several cm of Pb
E.g Cobalt-60 - cancer treatment

Question 5

Radioisotope

Answer 5

a radioactive isotope. an element that emits radiation

Question 6

Half-life

Answer 6

of an element is the time taken for half the nuclei of a radioactive sample to decay

Question 7

Radiocarbon dating

Answer 7

a technique used to find the age of an object containing carbon. It is based on the ratio of Carbon-12 and Carbon-14 in the object

Question 8

Nuclear reaction

Answer 8

is a process that alters the composition, structure or energy of an atomic nucleus

Question 9

Chemical reaction

Answer 9

involve changes in the sharing and transfer of electrons, whereas nuclear reactions involve changes in the nucleus

Question 10

Chemical reactions + Nuclear reactions differences

Answer 10

• CR involves electrons while NR involves the nucleus
• in CR no new elements are formed while in NR new elements are formed
• in CR there is no release of nuclear energy while in NR there is a release of nuclear energy
  -in CR bonds are broken and formed while NR no bonds are broken or formed