Section 7 - Atomic Physics Flashcards
What three things are in an atom?
Nucleus
Proton
Electron
What part of a atom is negatively charged?
The electron
What is the part of an atom with a positive charge?
Proton
What is found in the nucleus of an atom?
Protons and neutrons
Describe the structure of an atom?
An atom is a positively charged nucleus that contains protons and electrons with negatively charge electrons orbiting the nucleus
Explain the alpha scattering experiment?
A beam of alpha particles were shot at a thing sheet of gold.
Alpha particles are positively charged so returned atoms must be repelled.
What were the results of the alpha particles experiment?
Most alpha particles went straight through, some were deflected, and a tiny proportion bounced back
What do the reuse kits from the alpha particle experiment show?
- the nucleus is very small and surrounded by empty space
- a nucleus is positively charged as some particles were deflected
- a nucleus is very dense and contains most of the atoms mass
How do you find the proton number?
The proton number is the atomic number
What is the nucleon number?
The number of protons and neutrons - the atomic mass
What is the letter notation for the element symbol?
X
What is the letter notation for the atomic mass?
A
What is the letter notation for atomic number?
Z
What is an isotope?
An isotope is an atom with the same number of protons but a different number of electrons
What is radioactive decay?
Radioactive decay is the process in which unstable nuclei change to become more stable by emitting ionising radiation. This process is spontaneous and random
What is background radiation?
Background radiation is the radiation that is present all around in the environment
Name four background radiation examples?
- natural gas - radon
- rocks and buildings
- food and drink
- cosmic rays
How can nuclear radiation be detected?
Using a GM tube - detector and counter
What is radiation measured in?
Counts. Or counts per minute
Describe how radiation is emitted?
Radiation is emitted at a randomly and in any direction
What are the three types of radiation?
Gamma
Beta
Alpha
What is the ionising power of the three emissions?
Alpha - strong
Beta - moderate
Gamma - weak
What is the penetration power of all the emissions?
Alpha - weak - few cm in air or sheet of paper
Beta - moderate - few metres or thin aluminium
Gamma - strong - long distance or thick lead
Describe an alpha particle
An alpha particle consists of two protons and two neutrons (the same as a helium nucleus) it has no electrons
Describe a beta particle
A beta particle is a fast moving electron
Describe gamma radiation
Gamma are waves of the electromagnetic spectrum
What types of decay produce a new element
Alpha and beta
Describe alpha decay
Alpha decay is when a nucleus emits an alpha particle. The nucleus’ proton number will decrease by 2 and atomic mass decrease by 4
Describe beta decay
Beta decay is when a neutron turns into a proton and an electron.
The electron is the beta particle and the proton moves back into the nucleus. The proton increase by 1 and the atomic number stays same
What are three thing that make a nucleus unstable?
If they have too much energy
If they have too many neutrons
If they are too heavy
How is a alpha particle written
letter a with atomic number 4 and proton number 2
How is a beta particle written
B with a tail. Atomic mass 0 and proton number -1
What is half life?
Half life is the time taken for half the nuclei of that isotope of a sample to decay
