Radioactive gaseous (222,86)rn and (220,86)rn can be produced from the decay of uranium and thorium in rocks and soil.
(a) (222,86)rn is a decay product of (238,92)u, while (220,86)rn comes from (232,90)th. how many alpha particles are emitted in the formation of these radon isotopes from their uranium or thorium starting points? can alpha decay alone explain the formation of these radon isotopes? if not, state what other types of decay must occur.
(b) can (222,86)rn and (220,86)rn decay by alpha particle emission? write balanced nuclear equations for these two decay processes, and predict for each reaction whether it is allowed or not. the masses of (222,86)rn and (220,86)rn atoms are 222.01757 and 220.01140 u, respectively; those of electron, (4,2)he, (218,84)po and (216,84)po are 0.00055, 4.002602, 218.0089 and 216.00192 u, respectively.
(c) calculate the energy released in the alpha decay of one (220,86)rn nuc- leus, in million electron volts and in joules.
(d) the half-life of (222,86)rn is 3.82 days. calculate the initial activity of 2.00*10^(-8) g of (222,86)rn, in disintegrations per second. what will be the activity of the (222.86)rn after 14 days?
(e) the half-life of (220,86)rn is 54 s. are the health risks of exposure to a given amount of radon for a given short length of time greater or sma- ller for (220,86)rn than for (222,86)rn? radon, being gaseous, post high health risks. explain why radon is a gas.