1. Vertical columns are known as 2. Horizontal rows are known as 3. Group I elements are known as 4. Elements placed at the bottom of periodic table 5. Inner transition elements placed in sixth period 6. Number of elements in the first period 7. Elements of second period are known as 8. Longest period of the periodic table 9. Incomplete period of the periodic table 7 10. Zero group elements are also known as​