Master this deck with 51 terms through effective study methods.
Imported from Quizlet
Pos+ charged nucleus --> Proton (+1) & Neutron (0), Neg- charged electrons in energy levels (shells), Most of atom's mass in nucleus, Atom is mostly empty space
Pos+ ions/cations:, formed when atoms lose e-, Neg- ions/anions:, formed when gain e-
no. protons not = to no. e-
Most passed straight through, Some slightly deflect, Very few bounce back
Mostly empty space, Nucleus is dense, Pos+ charged nucleus bc pos+ alpha particles repel
1 x 10^-10m
1 x 10^-15m, Nucleus is 100k times smaller than atom
Proton, +1, 1, Neutron, 0, 1, Electron, −1, 1/1836 (very small)
Splitting heavy nucleus
Smaller nuclei, Neutrons, Energy, Can cause chain reaction
Fusing light nuclei
very high temp → happens in stars
more energy than fission
Formula: E = mc^2, E = energy released, M = mass, C = speed of light (3 x 10^8 m/s), Even if small mass lost → large energy released (bc c is so large), Explains energy in:, Fusion, fission
Alpha particles fired at thin foil, Alpha particles detected how they scatter
Nuclear charge = no. of protons (Z), Nuclear mass = nucleon no. (A),
low level radiation always present, Comes from natural + artificial sources
~85% of BR, Radon gas → from rocks (largest source), Rocks + buildings → radioactive materials, Food & drinks → contain small radioactive amounts, Cosmic rays → higher at altitude
~15% of BR, Medical use (x-rays, cancer treatment), Nuclear industry
Using geiger muller tube (GM) = counter, measures count rate (radiation detected)
Total count rate - bg. radiation
initial count rate/ 2^n (n = no. of half lives passed)
Nuclear radiation emitted from unstable nuclei, Emission is spontaneous + random in direction
Helium nucleus (2 proton + 2 neutron), Charge: 2+, Large mass
Low, Stopped by paper, Range in air = few cm
Very high bc large mass, Strong pos+ charge, Cause many collisions w/ atoms
Deflected by electric + mag field, Moves toward neg- plate, Deflects only slightly bc heavy
Fast moving e-, charge : -1, Very small mass
Moderate, Stopped by few mm of aluminium, Range in air: several metres
Moderate, Smaller charge + mass than alpha
Deflect by electric + mag fields, Moves towards pos+ plate, Deflect more than alpha (lighter)
EM wave, No mass, No charge
Very high, Stopped by thick lead/ concrete
Low, No charge bc weak interaction w/ atoms
Not deflated by elec./mag fields
thick, Straight
Thin, Curved, Twisted
No direct track, Prod e- that leave tracks
Atoms become diff. Element, Cause by:, Too many neutrons, Nucleus too heavy
Emits helium nucleus (2p + 2n), Nucleon no. -4, Proton no. -2, Makes nucleus more stable
e- emitted, Proton stays in nucleus → nucleon no. unchanged
Releases energy only, No change in:, Proton no., Nucleon no., Happens after alpha/beta decay
Stable nuclei depend on Z (proton) + N (neutron) ratio,
N = Z
N > Z
decay
Smoke alarms → alpha (bc short range + safe), Food irradiation + Sterilisation → gamma (kills bacteria), Cancer treatment → beta
Damage cells → cell death, Cause mutations → Leads to cancers, Alpha → dangerous if inside body, Beta & Gamma → dangerous externally
Reduce time of exposure, Increase distance, Use shielding:, Paper → alpha, Aluminium → beta, lead/concrete → gamma, Use tongs, Store in lead containers, Use lead/concrete shielding, Monitor exposure → film badges
emission of alpha/beta/gamma radiation from an unstable nucleus
time for half the nucleus to decay, Count Rate = Initial count rate/2^n, n = no. half life