LO 85 - 86 Flashcards
Given the isotope A Z X what does each letter represent?
A represents the mass number (proton + neutrons) of element X while Z represents the atomic number (protons)
1 1 p
proton
1 0 n
neutron
0 -1 e
electron
______________ decay occurs when an unstable nucleus emits a particle composed of two protons and two neutrons
Alpha (α)
α particle = ________
4 2 He
In alpha decay the mass number ________________ and the atomic number ____________________
decreases by 4
decreases by 2
Alpha particles have the highest _______________________ which can damage other molecules due to their size and activity
ionizing power
Alpha particles have the lowest ____________________ into matter and can be stopped by paper or clothing
penetrating power
_______________ decay occurs when an unstable nucleus emits an electron
Beta (β)
β particle = _____________
0 -1 e
What happens to the neutron in beta decay?
1 0 n → 1 1 p + 0 -1 e
In beta decay the mass number is _____________ while the atomic number __________________________
unchanged
increases by 1
beta decay is ___________ damaging than alpha decay but has a higher ____________
less
penetrating power
__________________ are a form of electromagnetic radiation that are high-energy, short-wavelength photons
Gamma (γ) rays
gamma ray =_______
0 0 γ
gamma rays are usually from ________ or in conjunction with processes such as _________________________
excited atoms
alpha / beta decay
After alpha or beta decay some atoms enter a ________ state before they release _____________
metastable
gamma rays
Gamma rays have the lowest __________________ but the highest __________________ that could need thick concrete to stop
ionizing power
penetrating power
_________________ occurs when an unstable nucleus emits a ______________, the antiparticle of an electron which collides with an e-, annihilate each other, and produce ____________
positron emission
positron
gamma rays
positron = ____________
0 +1 e
What happens to the proton in positron emission?
1 1 p → 0 +1 e + 1 0 n
In positron emission the mass number is ___________ while the atomic number _____________________
unchanged
decreases by 1
______________ involves a particle being absorbed not emitted and occurs when the nucleus assimilates an e- from an inner orbital
electron capture
What happens to the proton in electron capture?
1 1 p +0 -1 e → 1 0 n
In electron capture the mass number is ___________ while the atomic number _____________________
unchanged
decreases by 1
A nucleus is composed of ______________ which consists of the protons and neutrons. Since the positive force of the protons wants to repel the ___________ holds the nucleus together
nucleons
strong force
A high (>1) neutron/Atomic Number ratio (N/Z) tends to result in . . .
beta decay
A low (<1) neutron/Atomic Number ratio (N/Z) tends to result in . . .
positron emission or e- capture
A large number of the stable nuclei have an ________ number of protons and neutrons
even
Atoms with Z > ___ are radioactive and decay in one or more steps via alpha or beta decay
83
What are the magic numbers for unique nucleus stability?
N or Z = 2,8,20,28,50,82
N = 126
