False statement for periodic classification of element is

Options

A. The properties of the elements are periodic function of their atomic numbers.
B. No. of non-metallic elements is less than the no. of metallic elements
C. First ionization energy of elements does not change continuously with increasing of atomic no. in a period.
D. d-subshell is filled by final electron with increasing atomic no. of inner transition elements.

Answer

To determine the false statement regarding the periodic classification of elements, let's analyze each statement step by step:

### Step 1: Analyze the First Statement
**Statement:** Properties of elements are periodic functions of their atomic number.

**Analysis:** This statement is true. The periodic table is organized based on increasing atomic number, and the properties of elements show periodic trends as you move across periods and down groups. For example, elements in the same group often exhibit similar chemical properties due to their similar valence electron configurations.

### Step 2: Analyze the Second Statement
**Statement:** The number of non-metallic elements is less than the number of metallic elements.

**Analysis:** This statement is also true. In the periodic table, there are significantly more metals (approximately 80% of the elements) compared to non-metals. For instance, out of 118 known elements, around 90 are metals, indicating that non-metals are indeed fewer in number.

### Step 3: Analyze the Third Statement
**Statement:** The first ionization energy of the elements does not change continuously on increasing atomic number in a period.

**Analysis:** This statement is false. The first ionization energy generally increases as you move across a period due to the increasing effective nuclear charge, which holds the electrons more tightly. Therefore, it does change continuously and typically increases, contradicting the statement.

### Step 4: Analyze the Fourth Statement
**Statement:** D subshell electrons are filled with increasing atomic number by inner transition elements.

**Analysis:** This statement is true. In transition metals, the d subshell is filled progressively as the atomic number increases. However, there are exceptions where electrons may be removed from the s subshell to achieve a more stable electron configuration (e.g., in chromium and copper). This behavior is consistent with the filling of d orbitals.

### Conclusion
After analyzing all the statements, the false statement is:

**False Statement:** The first ionization energy of the elements does not change continuously on increasing atomic number in a period.