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 to_______________.
Who Am I? Identify the element using the information given below in questions 3-5.
Please 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 _______