7.for the following questions, use a periodic table and your atomic calculations to find the unknown information about each isotope: you have an neutrally charged isotope with 30 electrons and a mass number of 64. what element is it? cu: copper zn: zinc p: phosphorus se: selenium

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.