Question

the first \periodic table\ was created by △ who arranged the elements by △ △. our current periodic table was created by △ who arranged the elements by △ △. possible points: 9.09

Explanation:

1. The first periodic table - John Newlands arranged elements by atomic mass (law of octaves).
2. Current periodic table - Dmitri Mendeleev (arranged by atomic mass initially, but modern is by atomic number, though Mendeleev's work laid foundation; Henry Moseley later arranged by atomic number).

Answer:

First "periodic table": Created by John Newlands, arranged by atomic mass (law of octaves).
Current periodic table: Created by Dmitri Mendeleev (foundation) / Henry Moseley (modern, by atomic number); arranged by atomic number (modern) or initially atomic mass (Mendeleev).

(Note: For first, Newlands (octaves, atomic mass); for current, Mendeleev (atomic mass, left gaps) then Moseley (atomic number).)