chapter9

Question 1

radioactivity

Answer 1

the process by which an unstable nucleus emits one or more particles, OR energy in the form of electromagnetic radiation

Question 2

nuclear radiation

Answer 2

the particles that are released from the nucleus during radioactive decay.

Question 3

After the changes in the nucleus, the element can transform into

Answer 3

a different isotope of the same element or into an entirely different element.

Question 4

alpha particle

Answer 4

a positively charged atom that is released in the disintegration of radioactive elements and that consists of two protons and two neutrons i.e. He nucleus. massive but NOT very energetic.

Alpha particles can Ionize matter.

Question 5

beta particle

Answer 5

a charged (fast moving) electron emitted during certain types of radioactive decay, such as beta decay.

Beta particles can ionize matter.

Question 6

gamma radiation

Answer 6

high energy photon released by a nucleus during fission, and radioactive decay. Very high energy, and hazardous. Can penetrate 7mm of Pb.

Question 7

Gamma rays

Answer 7

High energy photons/EM radioation. Can ionize other matter. Very energetic

Question 8

Neutron emission

Answer 8

emission of a neutron from an unstable particle.

NO charge —> no matter ionization, as such they travel far through matter.

Question 9

alpha decay

Answer 9

A nucleus gives up two protons and two neutrons in the form of a He nucleus.

2 protons & 2 neutrons form a He nucleus.

Question 10

beta decay

Answer 10

emission of an electron whereby a neutron decays into a proton and electron.

So a nucleus gains a proton and loses a neutron, as it emits an electron.

Question 11

half life

Answer 11

the time required for half of a sample of a radioactive substance to disintegrate by radioactive decay, or by natural processes.

Question 12

Nuclear Radiation

Answer 12

may emitt alpha particles, beta particles, gamma rays, and neutrons.

Question 13

gamma radiation

Answer 13

electomagetic wave with lots of energy (high energy photon).

Question 14

Neutrons help keep nuclei together

Answer 14

the nucleus is held together by the attractions between protons and neutrons. These forces are greater than the electric repulsion among the protons alone.

Question 15

Unstable Nuclei: # of P > 83

Answer 15

Nuclei with more than 83 protons are always unstable, no matter how many neutrons they have.

Question 16

Fission

Answer 16

the process by which a nucleus splits into two or more fragments and releases neutrons and energy.

Question 17

mass defect

Answer 17

the total mass of a nucleus is less than the sum mass of all neutrons and protons comprising it.

Question 18

Nuclear Chain Reaction

Answer 18

continuous series of nuclear fission reactions.

Question 19

Critical Mass

Answer 19

the minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction.

Question 20

Nuclear Fusion

Answer 20

the process in which light nuclei combine at extremely high temperatures to, forming heavier nuclei and releasing energy.

Question 21

REM

Answer 21

the quantity of ionizing radiation that does as much damage to human tissue as 1 roentgen of high voltage X rays does.