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level: Atomic Structure

Questions and Answers List

level questions: Atomic Structure

QuestionAnswer
What must electrons absorb to move around/leave the atom?EM radiation (Electromagnetic)
What do electrons do once [_] is absorbed?They move to a higher energy level further from the nucleus
What happens if electrons release [_] instead of absorbing it?They move to a lower energy level closer to the nucleus
What ion is created if electrons leave the atom?A positively charged ion
What are alpha particles?Helium nuclei
Symbol for an alpha particle?Symbol:
How far can alpha particles travel in air?A few cm
What are alpha particles absorbed by?A piece of paper
Ionisation in alpha particles?Strongly ionising
Example of where alpha particles are usedIn smoke alarms
What are beta particles?High- Speed Electrons released from the nucleus
Symbol for a beta particle?Symbol:
How far can beta particles travel in air?A few metres
Ionisation in beta particles?Moderately ionising
What are beta particles absorbed by?A sheet of aluminium
What happens for every beta particle emmitted?A neutron in the the nucleus has turned into a proton
Example of where beta particles are usedBeta emitters that test the thickness of sheets of metal
What are gamma rays?Waves of electromagnetic radiation released by the nucleus
Symbol for a gamma ray?Symbol:
How far can gamma particles travel in air?Long distances
What are gamma particles absorbed by?Thick sheets of lead or concrete
Ionisation in gamma particlesWeakly ionising- don't usually collide with atoms
What has to balance?Atomic numbers and masses
Atomic decay equation?Atom before decay = atom after decay + radiation emitted
What happens to the atomic number and mass of an atom that endures alpha decay/ emits an alpha particle?Atomic number reduces by 2, mass reduces by 4
What happens to the atomic number and mass of an atom that endures beta decay/ emits a beta particle?Atomic number increases by 1 (neutron has been turned into a proton), mass doesn't change (electron lost but proton gained)
What happens to the atomic number and mass of an atom that endures gamma decay/ emits a gamma particle?There is no change. Energy is released from the atom.
What is radiation measured by?Geiger-Muller tube and counter
What does the [_] record?Number of radiation counts reaching it per second
What is half-life?The amount of time it taken for the number of radioactive nuclei in an isotope to halve
What is Activity?The rate of radioactive decay
What is the unit for Activity?Bq
What does a short half-life mean?The Activity will fall quickly because the nuclei in the isotope are very unstable and decay rapidly
What is irradiation?Exposure to radiation
What is contamination?Radioactive atoms getting onto or into an object
Which types of radiation are the most dangerous outside the body? Why?Beta and gamma- can penetrate skin
Which type of radiation is the most dangerous inside the body? Why?Alpha- damages in localised areas
Why are high doses of radiation dangerous?Can ionise atoms and molecules in living cells, killing them leading to radiation sickness