A rough estimate of the radius of a nucleus is provided by the formula r 5 kA1/3, where k is approximately 1.3 × 10-13 cm and A is the mass number of the nucleus. Estimate the density of the nucleus of 127I (which has anuclear mass of 2.1 × 10-22 g) in grams per cubic centimeter. Compare with the density of solid iodine, 4.93 g cm-3.

Calculate the mass of antimony(III) lodide, Sbl3, that can be produced by the reaction of 143 g of antimony, Sb (Z- 51), and 401 g of iodine. Also, find the mass in grams of the element that will be left. Iodine is a bluish-black lustrous solid at room conditions, as seen on the right. It readily sublimates -changes directly from solid to gas-to a blue- violet gas, as seen on the left. Mass of Sbl3 = Mass of element left =

A robot spacecraft returned samples from the planetesimal 98765 ALEKS, located in the outer Solar System. Mass-spectroscopic analysis produced the following data on the isotopes of molybdenum in these samples: mass relative isotope (amu) abundance 96- Мо 95.9 41.% 91 Mo 59.% 96.9 Use these measurements to complete the entry for molybdenum in the Periodic Table that would be used on 98765 ALEKS. Be sure your answers have the correct number of significant digits. Caution: your correct answer will have the same format but not necessarily the same numbers as the entry for molybdenum in the Periodic Table we use here on Earth. Mo

Predict which one is the most stable nucleus amongst _8 O^16, _8 O^17 and _8 O^18. ( In this case you have to differentiate w.r to A. See A is the variable in the isotope family. Then find the value of A and see which value is this A close to)

165 21. Identify the neutron-to-proton ratio for the isotope 67HO and determine if the isotope is stable. O 1.46: 1; stable O 1.46:1; unstable O 0.68: 1; stable O 0.68: 1; unstable Type here to search

the percentage of oxygen by weight in AL*2(SO*4)*3 atomic weight: al= 27, S= 32, O= 16