Radioactivity Calculations/Units Flashcards
Speed of light
3x10^8 m/s
How do you calculate binding energy in Joules
Energy=Mass(Kg) x (Speed of light)^2
How to calculate Mass defect
Mass of component parts (Kg/u) - Mass given in question (Kg/u). If in u, convert to Kg to find binding energy
What does t stand for in decay equation
Time elapsed
What does No stand for in decay equation
Isotope definitely
Different form of the same element with same number of protons but different number of neutrons
What does the mass number tell us
Identifies the element
What does the atomic mass number tell us
Identifies the isotope of an element
Converting years into seconds
x60x60x24x365
What is the binding energy per nucleon
The energy required to break down the nucleus into its constituent parts
What is the relation between the stability of an isotope and their binding energy/nucleon
The higher the binding energy, the more stable the nucleus.
What energy level does Lymaan drop to
Drops to n=1
What energy level does Bahmer drop to
N=2
What energy level does Peschan drop to
3
What spectrum is Lymaan
Ultraviolet
What spectrum is Bahmer
Visible light
What spectrum is Peschan
Infrared
Which of the three energy levels requires the most energy and why?
Lymaan as it takes a lot more energy to drop all the way down to n=1
Turning …x10^-7 to nanometres
x10^9
E=mc^2 what is c?
Speed of light
Stable nucleus
Even number of protons and neutrons
More protons means means more electrostatic repulsion force so more neutrons are needed to stop this.
Unstable nucleus
Too many protons and not enough neutrons to stop electrostatic force of repulsion
Why radioactive decay occurs
A nucleus is unstable and wants to become more stable so it must get rid of either a proton or a neutron to stabilise it.
Proton number
Z
Convert lamda to nano meters
X10^9 (-9)
Nano to mew(micro)
/1000
Plank’s constant
6.63x10^-34
Frequency unit
Hz
H
Plank’s constant
Metres to nano metres
x10^-9
Steps for wavelength transition calculations
Energy change, f=e/h, lambda=speed of light/f, convert to nm x10^-9, state spectrum
Discrete (whole number) energy levels
Because the electrons in an atom can only occupy certain, specific energy levels or orbitals, so they emit
characteristic spectra of elements (frequency and wavelength)
produced when the electrons in an atom or molecule transition between specific energy levels
why the visible emission spectrum of hydrogen has only a few lines
Hydrogen has one electron and most transitions
