Unit 4 Flashcards
Describe the plum pudding model
A sphere of positive charge with electrons spread throughout it
Describe how an electron can move between energy levels
An electron can move into a higher energy level by absorbing EM radiation
It can also move into a lower energy level by emitting EM radiation
What’s the type of particle created when an atom loses or gains electrons
ion
Describe how the subatomic particles are arranged in a nuclear model of an atom
The protons and neutrons are in the central nucleus and the electrons around the nucleus arranged in shells
An atom has 26 protons. State the number of electrons and explain why
26 electrons. Atoms in neutral. Protons and electrons have equal but opposite charges. For these charges to cancel there must be the same number of each
Define ionisation
An atom losing or gaining at least one electron electron
An electron is emitted from a nucleus. Explain the effect this has on the mass number and atomic number of the nucleus
The atomic number increases but the mass number stays the same. This is because emitting an electron involves a neutron turning into a proton
A student writes a nuclear Decay equation but he gets it wrong. How could he get it wrong
Have an equal atomic numbers on each side
Define half-life in terms of count rate
The time taken for the count rate of a sample to half
A Student predicts the activity of a sample for 500 million years in advance. Why is he likely to be wrong
Radioactive Decay is random and the effect of randomness on the activity will be greater for lower activities
Suggest two methods that workers could use to reduce their exposure to radiation in a radioactive power plant
Wearing protective suits
Using remote control arms
State the name given to the amount of radiation that an individual is exposed to
Radiation dose
State two things that can affect the amount of radiation that an individual is exposed to
Location and job
Explain the difference between contamination and irradiation
Contamination is where radioactive particles get onto an object. Irradiation is where an object is exposed to radiation
Give two ways in which a scientist can protect yourself against contamination when handling a radioactive sample
Wearing a protective suit and wearing gloves
Explain why an alpha emitter would not be used for medical imaging
Alpha radiation will be too dangerous inside the body I would not be detectable outside the body as it cannot penetrate tissue
Explain why an isotope with a short half-life must be used for medical imaging
A short half-life means the activity will quickly drop so the patient will not be exposed to radiation for too long
What occurs during nuclear fusion
A heavier nucleus is formed by joining two lighter nuclei which converts mass into energy
State one similarity between nuclear fusion and nuclear fission
They both release energy
State one difference between nuclear fusion and nuclear fission
Station is the splitting of a large nucleus to form a smaller nuclei where is fusion is the joining of smaller nuclei to form a larger one
Explain how the absorption of a neutron can lead to a chain reaction in a fission reactor
Absorbing a neutron makes the nucleus more unstable. The unstable nucleus undergoes fission. Patient is the splitting of an unstable nucleus into two lighter elements releasing 2 or 3 neutrons. These neutrons can be absorbed by other nuclei causing more fission. Each Decay can cause another to happen which is a chain reaction.
What is nuclear fission
The splitting of an unstable nucleus into two lighter elements and releasing 2 or 3 neutrons
Explain what would happen if a chain reaction is uncontrolled
Each fission Decay releases energy, so an uncontrolled chain reaction would release lots of energy which could lead to an explosion
