Question

Describe the main features of Modern Periodic Table

Answer 1

The long form of periodic table consist of vertical columns called groups and horizontal rows called periods. Elements are arranged in the increasing order of atomic numbers. Elements in the modern periodic table are arranged in 7 periods and 18 groups. ... The third period contains elements from Sodium to Argon.

Answer 2

Explanation:

The main features of modern periodic table The long form of periodic table consist of vertical columns called groups and horizontal rows called periods.

1. Elements are arranged in the increasing order of atomic numbers.
2. Elements in the modern periodic table are arranged in 7 periods and 18 groups.
3. Horizontal rows are called periods and vertical columns are called groups.
4. Elements are placed in periods based on the number of shells in their atoms.
5. The shortest period is the first period which contains only two elements – Hydrogen and Helium.
6. The second period contains elements from Lithium to Neon.
7. The third period contains elements from Sodium to Argon.
8. The fourth period contains elements from Potassium to Krypton.
9. The fifth period contains elements from Rubidium to Xenon.
10. Sixth period is considered as the longest periods in the periodic table. It contains elements from Cesium to Radon 
11. Seventh period is incomplete period
12. In group IIIB of the sixth period Lanthanides are placed.
13. In group IIIB of the seventh period Actinides are placed
14. In periodic table Lanthanides and Actinides are shown in the bottom of the periodic table.

The long form of periodic table consist of vertical columns called groups and horizontal rows called periods. Elements are arranged in the increasing order of atomic numbers. Elements in the modern periodic table are arranged in 7 periods and 18 groups. ... The third period contains elements from Sodium to Argon.

Hope it works..✌

please mark it as brainliest