Sagot :
Periods
are the horizontal ⇔ rows in the periodic table.
Groups
are the vertical ↑↓ column in the periodic table
are the horizontal ⇔ rows in the periodic table.
Groups
are the vertical ↑↓ column in the periodic table
horizontal row in periodic table is period
vertical row in periodic table is group or family
vertical row in periodic table is group or family