Chapter 1 - Matter and radiation Flashcards
Describe model of an atom
Positively charged nucleus (composed of protons and neutrons) surrounded by orbiting electrons
What is the charge of a proton?
1.6x10^-19C
What is the charge of an electron?
-1.6x10^-19C
equal and opposite to charge of proton
What is the charge of a neutron?
0
What is the mass of a nucleon (proton and neutron)?
1.67x10^-27Kg
What is the mass of an electron?
9.11x10^-31Kg
What is the atomic number of an element?
Number of protons
What is the mass number?
Number of protons and neutrons
Write the isotopic notation
a - number of protons/neutrons
X
z - number of protons
What are isotopes?
Atoms of an element with the same number of protons but different number of neutrons
What is specific charge?
Charge divided by mass of particle
‘specific means ‘per unit mass’
What is the specific charge of a proton?
Charge/mass = 1.6x10^-19C/1.67x10^-27Kg = 9.58x10^7CKg^-1
Which subatomic particle has the largest specific charge?
Electron
Calculate the specific charge of a 2+ magnesium ion?
Charge/mass = 3.2x10^-19/3.98x10^-26 = 8.04 x 10^6 CKg^-1
ignore mass of electrons when calculating specific charge of ion
What stops a stable nuclei from disintergrating?
Strong nuclear force
What does the strong nuclear force act between?
Nucleons (protons and neutrons)
Is the strong force attractive or repulsive?
Both
Why is the strong nuclear force attractive and repulsive?
Attractive to keep nucleons together but also repulsive to prevent nucleus collapsing
When is the strong nuclear force attractive?
From 3-4 fm to 0.5fm
What are the particles emitted by a unstable nucleus called?
Nuclear decay
Name the types of radiation emitted by an unstable nucleus
- Alpha radiation
- Beta radiation
- Gamma radiation
Which type of atoms feature alpha decay?
Very big atoms
Uranium and radium