1. the russian chemist who designed the first accepted version of periodic table in the 1800s was 2. the first accepted version of the periodic table was arranged by atomic mass, but the modern periodic table, that we use today, is arranged according who am i? identify the element using the information given below in questions 3-5. give the element symbol and be sure to write it in the correct format, for example: if the answer is bromine and you write br, it will be marked wrong, br is the correct element symbol. 3. i am in group 15 and period 3 4. i am in period 4 and group 13 5. i am in group 13 and period 2