Which of the following statement `(s)` is`//`are correct ?

Options

A. In Mendeleev periodic table, all groups are divided into two subgroups.
B. There is no relationship between electronic configuration of the elements and their position in the extended form of periodic table.
C. `s`-block elements have one or two electrons in their outermost shell.
D. Osmium has the maximum density among metals.

Explanation

To determine which statements are correct, we will analyze each statement one by one based on our understanding of the periodic table and the properties of elements.

### Step-by-Step Solution:

1. **Statement 1: In the Manly periodic table, all groups are divided into two subgroups.**
- This statement is **incorrect**. In the Manly periodic table, groups 1 to 7 are divided into two subgroups (A and B), but group 8 (noble gases) is not divided into subgroups. Therefore, this statement does not hold true.

2. **Statement 2: There is no relationship between the electronic configuration of an element and their position in the extended form of the periodic table.**
- This statement is also **incorrect**. The extended form of the periodic table is indeed based on the electronic configuration of elements. Elements in the same group have the same number of valence electrons, which directly relates to their electronic configuration. Hence, this statement is false.

3. **Statement 3: S-block elements have one or two electrons in their outermost shell.**
- This statement is **correct**. S-block elements, which include groups 1 and 2, have a general electronic configuration of ns¹ or ns², meaning they have one or two electrons in their outermost shell. Thus, this statement is true.

4. **Statement 4: Osmium has maximum density among metals.**
- This statement is **correct**. Osmium is known to have the highest density of all metals, with a density of approximately 22.65 g/cm³. Therefore, this statement is also true.

### Conclusion:
- The correct statements are **Statement 3** and **Statement 4**.

### Summary of Correct Statements:
- Statement 3: Correct
- Statement 4: Correct