Question

what are the sailent features of moedern periodic table

Answer 1

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

Answer 2

The salient features of the Modern periodic table are:

1. the periodic table has 18 vertical columns called groups. and seven horizontal rows called periods.

2. The elements of group 1,2, 13, 14, 15 , 16 and 17 are known as the main group or representative elements.

3.The elements of group 3,4,5,6,7,8,9, 10 ,11 and 12 are known as transition elements

4. Element 18 are called noble gases or inert gases.

5.The first period contains only 2 elements and is the shortest period.

6. The second and third period contain 8 elements and is called short period.

7. The fourth and fifth period contains 18 elements. these are long periods.

8. The sixth period contain 32 elements . it is longest period.

9. The seventh period is incomplete.

10. in group 3 of sixth period there is set of elements with atomic number 57  to 71 . they are known as lanthanides.

11. In group 3 of seventh period the elements with atomic number 89 -103 are known as actinides.