Which statement ( s) is are false for the periodic classification of element ?

Options

A. The properties of the element are the perioic functions of the their atomic number .
B. Non- metallic element are leasser in number than thte metallic elements
C. the first ionization energies of the elements along a period do not vary in a regular manner with increase in atomic number
D. For transition elements the d- elements are filled monotonically with increase in atomic number

Explanation

To determine which statements are false regarding the periodic classification of elements, we will analyze each statement one by one.

### Step 1: Analyze the Statements

1. **Properties of elements are a periodic function of their atomic number.**
- This statement is **true**. The periodic law states that the properties of elements are periodic functions of their atomic numbers.

2. **Elements are arranged in the increasing order of their atomic number.**
- This statement is **true**. The modern periodic table is arranged by increasing atomic number.

3. **The non-metallic elements are less than the metallic elements.**
- This statement is **false**. There are more non-metallic elements than metallic elements in the periodic table.

4. **The first ionization energy of the elements does not vary in a regular manner with an increase in atomic number.**
- This statement is **false**. The first ionization energy generally increases across a period and decreases down a group, showing a regular pattern.

5. **The size of nitrogen is greater than the size of oxygen.**
- This statement is **false**. Oxygen is smaller than nitrogen due to increased nuclear charge, which pulls the electrons closer to the nucleus.

6. **The non-metallic elements are filled monotonically with an increase in atomic number.**
- This statement is **true**. Non-metals typically increase in number as you move across periods.

7. **The non-metallic elements do not fill monotonically with an increase in atomic number.**
- This statement is **false**. As mentioned earlier, non-metallic elements do fill monotonically with an increase in atomic number.

### Step 2: Identify the False Statements

Based on the analysis, the false statements are:

- The non-metallic elements are less than the metallic elements.
- The first ionization energy of the elements does not vary in a regular manner with an increase in atomic number.
- The size of nitrogen is greater than the size of oxygen.
- The non-metallic elements do not fill monotonically with an increase in atomic number.

### Final Answer

The false statements regarding the periodic classification of elements are:
1. The non-metallic elements are less than the metallic elements.
2. The first ionization energy of the elements does not vary in a regular manner with an increase in atomic number.
3. The size of nitrogen is greater than the size of oxygen.
4. The non-metallic elements do not fill monotonically with an increase in atomic number.

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