The modern periodic law states that the physical and chemical properties of elements are periodic functions of their atomic numbers. This is an updated version of the original periodic law proposed by Dmitri Mendeleev, which was based on the increasing atomic masses of elements.
**Basis of the Modern Periodic Law:**
The modern periodic law is based on the arrangement of elements in the periodic table according to their atomic numbers. The atomic number of an element is the number of protons in the nucleus of its atoms. The key points supporting the modern periodic law are:
1. **Arrangement by Atomic Number:**
- Elements are arranged in the periodic table in order of increasing atomic number, not atomic mass. This is because the atomic number uniquely identifies an element, and it reflects the number of protons in the nucleus.
2. **Periodic Repetition of Properties:**
- The properties of elements are a periodic function of their atomic numbers. This means that as you move across a period (horizontal row) or down a group (vertical column) in the periodic table, there is a regular repetition of properties.
3. **Similar Chemical Behavior:**
- Elements with similar chemical properties are found in the same group. The vertical columns in the periodic table are called groups, and elements in the same group often exhibit similar chemical behavior due to similar electron configurations in their outer shells.
4. **Transition Elements:**
- The transition elements are placed in the center of the periodic table, between groups 2 and 13. Their properties are transitional between the highly reactive alkali and alkaline earth metals and the less reactive metals in groups 3 to 12.
5. **Lanthanides and Actinides:**
- The lanthanides and actinides, often placed below the main body of the periodic table, are part of the overall periodicity. They are included in the periodic table to maintain the order of increasing atomic numbers.
The modern periodic law provides a more accurate and comprehensive understanding of the relationships between the properties of elements. It reflects the organization of elements based on their fundamental atomic structure, specifically their atomic numbers, which has proven to be a more reliable indicator of an element's properties than its atomic mass.
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According to modern periodic law, the physical and chemical properties of elements are periodic function of their atomic numbers.
The basis of this law is "atomic number.
Answer:
The modern periodic law states that the physical and chemical properties of elements are periodic functions of their atomic numbers. This is an updated version of the original periodic law proposed by Dmitri Mendeleev, which was based on the increasing atomic masses of elements.
**Basis of the Modern Periodic Law:**
The modern periodic law is based on the arrangement of elements in the periodic table according to their atomic numbers. The atomic number of an element is the number of protons in the nucleus of its atoms. The key points supporting the modern periodic law are:
1. **Arrangement by Atomic Number:**
- Elements are arranged in the periodic table in order of increasing atomic number, not atomic mass. This is because the atomic number uniquely identifies an element, and it reflects the number of protons in the nucleus.
2. **Periodic Repetition of Properties:**
- The properties of elements are a periodic function of their atomic numbers. This means that as you move across a period (horizontal row) or down a group (vertical column) in the periodic table, there is a regular repetition of properties.
3. **Similar Chemical Behavior:**
- Elements with similar chemical properties are found in the same group. The vertical columns in the periodic table are called groups, and elements in the same group often exhibit similar chemical behavior due to similar electron configurations in their outer shells.
4. **Transition Elements:**
- The transition elements are placed in the center of the periodic table, between groups 2 and 13. Their properties are transitional between the highly reactive alkali and alkaline earth metals and the less reactive metals in groups 3 to 12.
5. **Lanthanides and Actinides:**
- The lanthanides and actinides, often placed below the main body of the periodic table, are part of the overall periodicity. They are included in the periodic table to maintain the order of increasing atomic numbers.
The modern periodic law provides a more accurate and comprehensive understanding of the relationships between the properties of elements. It reflects the organization of elements based on their fundamental atomic structure, specifically their atomic numbers, which has proven to be a more reliable indicator of an element's properties than its atomic mass.