Atomic Structure Flashcards
What is the charge of a proton?
+1.60 x 10^-19 coulombs
What are nucleons?
Protons and neutrons.
What is the mass of a proton?
1.67 x 10^-27 kilograms
What is the charge of a neutron?
0
What is the mass of a neutron?
1.67 x 10^-27 kilograms
What is the charge of an electron?
-1.60 x 10^-19 coulombs
What is the mass of an electron?
9.11 x 10^-31
What is the proton number?
Number of protons in an atom.
What is the symbol of the proton number?
Z
What is the nucleon number?
The number of protons and neutrons in an atom.
What is the symbol for the nucleon number?
A
What is the specific charge of a particle?
The ratio of a particles charge to it’s mass.
What is the equation for calculating specific charge?
Specific charge = charge/mass
What is the unit for specific charge?
Coulombs/kg (CKg^-1)
What is an isotope?
An atom with the same number of protons but different numbers of neutrons.
Name the three main forces acting on the nucleus.
- electromagnetic force
- gravitational force
- strong nuclear force
What role does the electromagnetic force play inside the atom?
Causes positively charged protons in the nucleus to repel each other.
What role does gravitational force play inside the atom?
Causes all the nucleons in the nucleus to attract each other due to their mass.
What role does the strong nuclear force play inside the nucleus?
The repulsive electromagnetic force is much larger than the attractive gravitational force. This means there is another force holding the nucleus together. This is the SNF.
What is the range of the strong nuclear force?
A few femtometres ( 1 fm = 1 x 10^-15) - the size of a nucleus.
What prevents the strong nuclear force from crushing the nucleus?
The SNF must be repulsive at very small separations.
What conclusion can be drawn from the fact that the size of the SNF is the same whether between proton-proton, neutron-proton, neutron-neutron?
The strong nuclear force works equally between all nucleons.
What is nuclear decay?
The emission of unstable particles from the nuclei.
When does alpha decay occur?
Alpha decay occurs in atoms that contain 82 or more protons.
Why does alpha decay occur?
The nuclei is too big for the strong nuclear force to keep them stable.
State the nucleon and proton number of an alpha particle.
Nucleon number - 4
Proton number - 2
By what amount does the nucleon and proton number of the atom, that the alpha particle is emitted from, decrease by?
Nucleon number decrease by 4.
Proton number decreases by 2.
What is beta-minus decay?
The emission of an electron from the nucleus along with an anti neutrino particle.
When does beta-minus decay?
Beta-minus decay happens in isotopes that are “neutron rich” - an isotope that has too many neutrons compared to protons.
What happens when a beta particle is emitted from an isotope?
- a neutron in the nucleus changes to a proton.
- the proton number increases by one.
- nucleon number stays the same.
What is the purpose of the anti-neutrino particle in beta-minus decay?
The antineutrino particle carries away some energy and momentum.
