revising 0.0 / 5 ? SciencetestGCSENone Created by: amylCreated on: 25-02-20 14:46 What is the radius of a nucleus? 1/10,000 of the radius of an atom. 1 of 26 What is the radius of an atom? 1 x 10-10m 2 of 26 Describe the structure of an atom? A positively charged nucleus containing protons and neutrons, surrounded by electrons on shells. 3 of 26 What are the properties of protons? charge +1 mass = 1 4 of 26 What are the properties of neutrons? Neutral charge and a mass = 1 5 of 26 What are the properties of electrons? Charge -1 and a mass very close to zero 6 of 26 Why do atoms have no overall charge? Equal number of protons and electrons and neutrons have no charge. 7 of 26 What is the atomic number of an element? The number of protons (small number) 8 of 26 What is the mass number of an element? The number of protons and neutrons (big number) 9 of 26 What is an isotope? An element with the same number of protons but a different number of neutrons. 10 of 26 What is alpha radiation? 2 protons and 2 neutrons 11 of 26 What is alpha radiation blocked by? Paper or a few cm of air 12 of 26 What is beta radiation? a high energy electron 13 of 26 What is beta radiation blocked by? Thin aluminium and a few metres of air 14 of 26 What is gamma radiation? EM wave 15 of 26 What is gamma radiation blocked by? Thick lead or thick concrete as it is the most penetrating. 16 of 26 How far can gamma radiation travel in air? ～500m 17 of 26 What is the symbol for alpha radiation? a 18 of 26 What is the symbol for beta radiation? β 19 of 26 What is the symbol for gamma radiation? ℽ 20 of 26 Define the half-life of a radioactive isotope? The time taken for the number of nuclei of a radioactive sample to halve. 21 of 26 Hydrogen has two radioactive isotopes H2 and H3- will they have the same half life? No as each isotope has its own half life value. 22 of 26 Strontium has a half life of one day. A sample contains 2400 strontium nuclei. How many will be left after 4 days? 150 radioactive nuclei. The remaining 2250 are still there but are now stable. 23 of 26 What is radioactive contamination? The unwanted presence of radioactive atoms on other materials. 24 of 26 Why is radioactive contamination a hazard? The radioactive nuclei decaying and emitting radiation. 25 of 26 What is radioactive irradiation? A material being exposed to emitted radiation. 26 of 26
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