Estimating for atomic number for an "unknown element" A questions tells me there's this element with 3 isotopes (270.51 amu, 34.07% abundance; 271.23 amu, 55.12%; and 269.14 amu, 10.81%), and to solve for average atomic mass. I have done so and got 271 (270.758) for its atomic mass. Then it asks me to estimate its atomic number, and its location on the periodic table. How do I exactly "estimate"? 

ps. I dont think this element actually exists...
Well I found it out. It is seaborgium atomic number 106, mass number 271.

To be found in period B6, group 7.