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Who first proposed the periodic table in 1869?
Who first proposed the periodic table in 1869?
What is the central topic in ICSE Class 9 Chemistry?
What is the central topic in ICSE Class 9 Chemistry?
What concept groups elements into three periods based on their atomic number?
What concept groups elements into three periods based on their atomic number?
What type of elements are found in the first column of the periodic table?
What type of elements are found in the first column of the periodic table?
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What type of elements are found in the second column of the periodic table?
What type of elements are found in the second column of the periodic table?
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What does the periodic table organize elements based on?
What does the periodic table organize elements based on?
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What is the main topic of the passage?
What is the main topic of the passage?
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Who proposed the Law of Octaves?
Who proposed the Law of Octaves?
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What is the significance of Dmitri Mendeleev's contribution?
What is the significance of Dmitri Mendeleev's contribution?
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What is the meaning of periodicity in the periodic table?
What is the meaning of periodicity in the periodic table?
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What happens to ionic radii as elements become larger in the periodic table?
What happens to ionic radii as elements become larger in the periodic table?
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What is the trend for ionization energy as elements become larger?
What is the trend for ionization energy as elements become larger?
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What is meant by electronegativity?
What is meant by electronegativity?
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What did Dmitri Mendeleev's periodic law propose?
What did Dmitri Mendeleev's periodic law propose?
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Who founded the Gupta Empire?
Who founded the Gupta Empire?
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Which ruler is often considered the glory period of the Gupta Empire?
Which ruler is often considered the glory period of the Gupta Empire?
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During the Gupta period, which style of temple architecture began to emerge?
During the Gupta period, which style of temple architecture began to emerge?
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Who made significant advancements in astronomy, mathematics, and other scientific fields during the Gupta period?
Who made significant advancements in astronomy, mathematics, and other scientific fields during the Gupta period?
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What is the capital city of the Guptas?
What is the capital city of the Guptas?
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Which period is known as the Golden Age of Indian culture?
Which period is known as the Golden Age of Indian culture?
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Study Notes
Chemistry Class 9 ICSE: The Periodic Table and Periodicity
The periodic table is a central topic in ICSE Class 9 Chemistry, as it helps students understand the arrangement of elements and their properties based on their atomic number. In this article, we will focus on the periodic table and its subtopics, such as Dobereiner's Triad, Newlan's Law of Octaves, and the contributions of Mendeleev.
The Periodic Table
The periodic table is a table that organizes elements based on their atomic number, showing a periodic repetition in their properties. It was first proposed by Dmitri Mendeleev in 1869 and has since been refined and expanded to include more elements as needed. The periodic table is divided into groups and periods, with each group containing elements that have similar chemical properties.
Dobereiner's Triad
Dobereiner's Triad is a concept that groups elements into three periods based on their atomic number. The triad consists of:
- Alkali metals: Elements in the first column of the periodic table, such as sodium (Na) and potassium (K), are highly reactive and form strong bonds.
- Alkali earth metals: Elements in the second column, such as calcium (Ca) and magnesium (Mg), are less reactive than alkali metals but still form strong bonds.
- Transition metals: Elements in the third column, such as iron (Fe) and copper (Cu), form weak bonds and have various oxidation states.
Newlan's Law of Octaves
Newlan's Law of Octaves states that every eight elements in the periodic table form a new group with similar properties. This law was proposed by Sydney Newlan in 1917 and has been supported by subsequent discoveries in atomic structure and chemical bonding.
Contributions of Mendeleev
Dmitri Mendeleev played a crucial role in the development of the periodic table. He proposed the first periodic law of chemical properties in 1858, which stated that elements arrange themselves in the periodic table in order of increasing atomic weight and that each element is followed in the order of increasing atomic weight by two elements that have almost the same properties, forming a periodic repetition. This law laid the foundation for the modern periodic table and allowed for a better understanding of the relationships between elements and their properties.
Periodicity in the Periodic Table
Periodicity in the periodic table refers to the recurring patterns in the properties of elements as they are arranged in order of increasing atomic number. Some key aspects of periodicity include:
- Atomic size: As elements become larger in the periodic table, their ionic radii increase, and their electrons are arranged in higher energy levels.
- Ionization energy: The energy required to remove an electron from an atom increases as elements become larger in the periodic table.
- Electronegativity: The tendency of an atom to lose electrons increases as elements become larger in the periodic table.
- Oxidation states: As elements become larger in the periodic table, they tend to have higher oxidation states, which means they can form more complex ions.
In conclusion, the periodic table is a fundamental concept in ICSE Class 9 Chemistry, providing a framework for understanding the arrangement of elements and their properties. By studying the periodic table and its subtopics, students can develop a deeper understanding of the relationships between elements and their properties, which is essential for success in the ICSE examinations.
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Description
Test your knowledge of the periodic table and its subtopics, including Dobereiner's Triad, Newlan's Law of Octaves, and Mendeleev's contributions. Explore the concepts of periodicity, atomic size, ionization energy, electronegativity, and oxidation states as they relate to the arrangement of elements and their properties.
