How to read it
Groups go down
Each column is a group. Elements in a group have the same number of outer electrons, so they react in similar ways.
Periods go across
Each row is a period. Moving right adds one proton and one electron at a time; moving down adds a whole new electron shell.
Spot the staircase
Turn on “Metalloids”. They form a zig-zag line: metals sit to its left, non-metals to its right.