Nuclear Phenomena Flashcards Preview

MCAT Physical Sciences > Nuclear Phenomena > Flashcards

Flashcards in Nuclear Phenomena Deck (15):
1

Atomic Number (Z)

The number of protons in the nucleus

2

Mass Number (A)

A = N + Z

3

Isotope

Same element, different numbers of neutrons

4

Atomic Mass Unit

1 amu = 1/12 mass of neutral Carbon-12 atom = 1.66 X 10^-27 kg = 1.66 X 10^-24 g

5

Nuclear Binding Energy

Energy that holds nucleus together defined by E = mc^2

6

Mass Defect

Difference between atom's atomic mass and sum of masses of its protons and neutrons.

7

Fusion

Two or more smaller nuclei combine to form larger nucleus

8

Fission

Large nucleus splits into smaller nuclei

9

Why do nuclear fusion and nuclear fission release energy?

initial mass > final mass

10

Alpha Decay

Emission of alpha particle (a Helium atom)
Subtract two protons and two neutrons

11

Beta Decay

Emission of a beta particle (an electron)
Add a proton when electron emitted, subtract one when positron emitted

12

Gamma Decay

Emission of high energy photons, does not change mass or proton number

13

Electron Capture

Nucleus captures inner-shell electron leading to neutron formation, so atomic number decreases by 1, but atomic mass remains the same

14

Half-Life

T(1/2) = ln 2/λ
Fraction of original nuclei remaining after n half-lives is (1/2)^n

15

Exponential Decay

-λn = Δn/ Δt
Number of nuclei that decayed in time t = n(0) - n
n = n(0)e^-λt