One alpha particle leaves a nucleus. How do mass and charge change?
- Mass down 4, charge down 2
- Mass unchanged, charge up 1
- Mass down 1, charge unchanged
A nucleus is neutron-heavy for its size. Which decay do you predict?
- Alpha emission
- Beta minus: a neutron becomes a proton plus an electron
- Electron capture
Gamma emission changes the mass number of the nucleus.
En entourer un : Vrai Faux
Polonium-210 (charge 84) alpha decays. Type the daughter's charge number.
Réponse : ______________
Uranium-238 (charge 92) emits one alpha particle. What is the daughter?
- Uranium-234 (92)
- Protactinium-234 (91)
- Thorium-234 (90)
Potassium-40 captures an inner electron. What changes?
- Mass down 4, charge down 2
- Charge down one, mass unchanged
- Charge up one, mass unchanged
U-238 became Th-234 by alpha. Th-234 next decays with a 24-day half-life. Which particle leaves?
- An electron
- An alpha particle
- A positron
A student says beta electrons orbited the atom before release. What is wrong?
- Electrons cannot leave atoms at all
- Gamma rays always carry them away
- The electron is created in the nucleus during decay
Which decay a nucleus chooses W1-mt_b_imidwJeQ-s1
- Mass down 4, charge down 2 · An alpha is two protons plus two neutrons, so both tallies drop together.
- Beta minus: a neutron becomes a proton plus an electron · Extra neutrons shed an electron as one converts to a proton, moving toward stability.
- Faux · Gamma only dumps leftover excitation energy, leaving mass and charge untouched.
- 82 · Charge 84 minus the alpha's 2 gives daughter charge 82.
- Thorium-234 (90) · Subtract 4 in mass and 2 in charge: 238 becomes 234, and 92 becomes 90.
- Charge down one, mass unchanged · A proton plus the electron becomes a neutron, so charge drops with mass steady.
- An electron · Th-234 beta decays to protactinium-234, releasing an electron.
- The electron is created in the nucleus during decay · The electron is produced at the decay moment, never parked in the nucleus beforehand.