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Questions and Answers
Lother Meyer's work in 1869 involved plotting physical properties of elements against what?
Lother Meyer's work in 1869 involved plotting physical properties of elements against what?
- Chemical reactivity series
- Atomic weights (correct)
- Electron configurations
- Number of neutrons in the nucleus
What was the most significant basis for Mendeleev's arrangement of elements in his periodic table?
What was the most significant basis for Mendeleev's arrangement of elements in his periodic table?
- Increasing order of atomic masses and similar properties (correct)
- Electron negativity and ionization energy
- Alphabetical order of element names
- Increasing order of atomic numbers
Mendeleev's Periodic Law states that the properties of elements are a periodic function of which of the following?
Mendeleev's Periodic Law states that the properties of elements are a periodic function of which of the following?
- Their electron configurations
- Their atomic masses (correct)
- Their physical state at room temperature
- Their chemical reactivity
What did Mendeleev do to accommodate elements that were unknown during his time?
What did Mendeleev do to accommodate elements that were unknown during his time?
What did Mendeleev use as a prefix to name the undiscovered elements?
What did Mendeleev use as a prefix to name the undiscovered elements?
Which element's existence and properties did Mendeleev predict by naming it Eka-aluminium?
Which element's existence and properties did Mendeleev predict by naming it Eka-aluminium?
What are the vertical columns in Mendeleev’s periodic table known as?
What are the vertical columns in Mendeleev’s periodic table known as?
What are the horizontal rows in Mendeleev’s periodic table known as?
What are the horizontal rows in Mendeleev’s periodic table known as?
What would be the temporary name and symbol for an element with an atomic number of 120, following IUPAC nomenclature rules?
What would be the temporary name and symbol for an element with an atomic number of 120, following IUPAC nomenclature rules?
An element is temporarily named 'Ununseptium'. What is its atomic number?
An element is temporarily named 'Ununseptium'. What is its atomic number?
Which of the following elements from the third period requires the fewest electrons to achieve a stable noble gas configuration?
Which of the following elements from the third period requires the fewest electrons to achieve a stable noble gas configuration?
An element has an electronic configuration of 2, 8, 6. What is the valency of this element?
An element has an electronic configuration of 2, 8, 6. What is the valency of this element?
Element X has the temporary IUPAC name of 'Ununbium'. If element X loses two electrons to form a stable ion, what would be the charge of the resulting ion?
Element X has the temporary IUPAC name of 'Ununbium'. If element X loses two electrons to form a stable ion, what would be the charge of the resulting ion?
Which of the following elements is most likely to gain two electrons to achieve a noble gas configuration?
Which of the following elements is most likely to gain two electrons to achieve a noble gas configuration?
Element 'Uno' is in the same group as which of the following elements?
Element 'Uno' is in the same group as which of the following elements?
If an element has a valency of 3 and belongs to the third period, which of the following could it be?
If an element has a valency of 3 and belongs to the third period, which of the following could it be?
Newlands' Law of Octaves demonstrated an early attempt to organize elements based on which fundamental property?
Newlands' Law of Octaves demonstrated an early attempt to organize elements based on which fundamental property?
Up to which element was Newlands' Law of Octaves found to be generally applicable without significant exceptions?
Up to which element was Newlands' Law of Octaves found to be generally applicable without significant exceptions?
What was one of the primary assumptions made by Newlands that later proved to be a limitation of his Law of Octaves?
What was one of the primary assumptions made by Newlands that later proved to be a limitation of his Law of Octaves?
According to Newlands' organization, cobalt and nickel were placed in the same group as which two elements, despite having different properties?
According to Newlands' organization, cobalt and nickel were placed in the same group as which two elements, despite having different properties?
The placement of iron in Newlands' table was considered inconsistent because, although its properties were similar to cobalt and nickel, it was:
The placement of iron in Newlands' table was considered inconsistent because, although its properties were similar to cobalt and nickel, it was:
Why was Newlands' Law of Octaves not widely accepted by the scientific community at the time of its proposal?
Why was Newlands' Law of Octaves not widely accepted by the scientific community at the time of its proposal?
How did the discovery of new elements after Newlands proposed his Law of Octaves contribute to its eventual decline?
How did the discovery of new elements after Newlands proposed his Law of Octaves contribute to its eventual decline?
Which of the following statements best describes the overarching significance of Newlands' Law of Octaves, despite its limitations?
Which of the following statements best describes the overarching significance of Newlands' Law of Octaves, despite its limitations?
Döbereiner's Law of Triads is based on the observation that elements with similar chemical properties can be grouped in threes. According to this law, what relationship exists between the atomic masses of the elements within a triad?
Döbereiner's Law of Triads is based on the observation that elements with similar chemical properties can be grouped in threes. According to this law, what relationship exists between the atomic masses of the elements within a triad?
How does the valency of elements typically change as you move from left to right across a period in the periodic table?
How does the valency of elements typically change as you move from left to right across a period in the periodic table?
If element X has an atomic mass of 30 and element Z has an atomic mass of 70, and these elements form a Döbereiner triad with element Y, what would be the approximate atomic mass of element Y, assuming Döbereiner’s Law holds true?
If element X has an atomic mass of 30 and element Z has an atomic mass of 70, and these elements form a Döbereiner triad with element Y, what would be the approximate atomic mass of element Y, assuming Döbereiner’s Law holds true?
Which of the following best explains why Döbereiner's Triads were not universally accepted as a method for classifying all known elements?
Which of the following best explains why Döbereiner's Triads were not universally accepted as a method for classifying all known elements?
Which of the following statements accurately describes the trend in valency when moving down a group in the periodic table?
Which of the following statements accurately describes the trend in valency when moving down a group in the periodic table?
Which of the following statements accurately describes a key difference between Doberiener's Triads and the modern periodic table?
Which of the following statements accurately describes a key difference between Doberiener's Triads and the modern periodic table?
Element X has an electronic configuration of 2, 8, 6. What is its valency?
Element X has an electronic configuration of 2, 8, 6. What is its valency?
How does atomic size generally change as you move down a group in the periodic table?
How does atomic size generally change as you move down a group in the periodic table?
Suppose three elements, A, B, and C, form a Döbereiner triad. Element A has an atomic mass of 14, and element C has an atomic mass of 46. Based solely on this information and Döbereiner's Law of Triads, predict the atomic mass of element B.
Suppose three elements, A, B, and C, form a Döbereiner triad. Element A has an atomic mass of 14, and element C has an atomic mass of 46. Based solely on this information and Döbereiner's Law of Triads, predict the atomic mass of element B.
Why do metals tend to lose electrons and form positive ions (cations)?
Why do metals tend to lose electrons and form positive ions (cations)?
Which of the following is a limitation of Döbereiner's classification of elements into triads?
Which of the following is a limitation of Döbereiner's classification of elements into triads?
How is the metallic character of elements related to their position on the periodic table, specifically when moving across a period from left to right?
How is the metallic character of elements related to their position on the periodic table, specifically when moving across a period from left to right?
Which of the following sets of elements could potentially form a Dobereiner triad? (Atomic masses are approximate)
Which of the following sets of elements could potentially form a Dobereiner triad? (Atomic masses are approximate)
A scientist discovers a new element and hypothesizes that it belongs to a Dobereiner triad with known elements P and Q. Element P has an atomic mass of 55, and element Q has an atomic mass of 125. If Dobereiner's Law holds, what experimental evidence would best support this hypothesis regarding the new element's properties?
A scientist discovers a new element and hypothesizes that it belongs to a Dobereiner triad with known elements P and Q. Element P has an atomic mass of 55, and element Q has an atomic mass of 125. If Dobereiner's Law holds, what experimental evidence would best support this hypothesis regarding the new element's properties?
Element Q is in Group 15. How many valence electrons does it have, and what is a common valency it exhibits?
Element Q is in Group 15. How many valence electrons does it have, and what is a common valency it exhibits?
If an element has a high tendency to lose electrons, which of the following characteristics is it most likely to possess?
If an element has a high tendency to lose electrons, which of the following characteristics is it most likely to possess?
Consider elements from the second and third periods. How does the change in effective nuclear charge affect both atomic radius and ionization energy?
Consider elements from the second and third periods. How does the change in effective nuclear charge affect both atomic radius and ionization energy?
Why does metallic character generally increase as you move down a group in the periodic table?
Why does metallic character generally increase as you move down a group in the periodic table?
An element has a low ionization energy and readily loses electrons in chemical reactions. Which of the following properties would you expect this element to possess?
An element has a low ionization energy and readily loses electrons in chemical reactions. Which of the following properties would you expect this element to possess?
Across a row of the periodic table, electronegativity increases. What is the primary reason for this trend?
Across a row of the periodic table, electronegativity increases. What is the primary reason for this trend?
How does the presence of intervening electrons between the nucleus and valence shell influence the ionization potential as you move down a group?
How does the presence of intervening electrons between the nucleus and valence shell influence the ionization potential as you move down a group?
Flashcards
How many elements are known?
How many elements are known?
The current number of known elements.
Element arrangement
Element arrangement
Arranging elements by similar properties, like a grocery store organizes items.
Who was Johann Wolfgang Dobereiner?
Who was Johann Wolfgang Dobereiner?
He classified elements into triads based on similar properties in 1829.
What are triads?
What are triads?
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Law of Triads
Law of Triads
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Mass number
Mass number
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Example of Dobereiner's Triad
Example of Dobereiner's Triad
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Non-metal Triad Example
Non-metal Triad Example
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Newlands' Atomic Arrangement
Newlands' Atomic Arrangement
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Octaves' Limited Scope
Octaves' Limited Scope
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Octaves and Calcium
Octaves and Calcium
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Newlands' Element Prediction
Newlands' Element Prediction
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Elements Defying Octaves
Elements Defying Octaves
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Cobalt and Nickel Placement
Cobalt and Nickel Placement
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Iron's Displaced Position
Iron's Displaced Position
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Law of Octaves
Law of Octaves
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Lother Meyer's element arrangement
Lother Meyer's element arrangement
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Meyer's Periodic Variation
Meyer's Periodic Variation
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Dmitri Mendeleev's Contribution
Dmitri Mendeleev's Contribution
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Mendeleev's Arrangement
Mendeleev's Arrangement
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Mendeleev's Periodic Law
Mendeleev's Periodic Law
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Groups vs. Periods
Groups vs. Periods
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Mendeleev's Gaps
Mendeleev's Gaps
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Eka- Prefix
Eka- Prefix
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Valence Shell
Valence Shell
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Valency
Valency
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Valency across a period
Valency across a period
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Valence electrons in a group
Valence electrons in a group
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Valency down a group
Valency down a group
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Atomic Size
Atomic Size
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Metals and electron loss
Metals and electron loss
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Atomic size across a period
Atomic size across a period
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Unnilunium
Unnilunium
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Rutherfordium
Rutherfordium
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Period Trend
Period Trend
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Noble gas configuration
Noble gas configuration
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Third Period Elements
Third Period Elements
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Sodium Configuration
Sodium Configuration
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Ionization Potential
Ionization Potential
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Ionization Potential Across a Period
Ionization Potential Across a Period
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Ionization Potential Down a Group
Ionization Potential Down a Group
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Electronegativity
Electronegativity
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Metallic Character
Metallic Character
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Study Notes
- The study of Periodic Classification of Elements involves understanding how elements with similar properties are arranged.
Doberiener's Triads and Newlands Law of Octaves
- Currently, 118 elements are known, some sharing similar properties while others contrast.
- Scientists sought patterns to arrange elements based on their properties.
Doberiener's Triads
- In 1829, Johann Wolfgang Dobereiner, a German chemist, grouped elements with similar properties into triads.
- Triads are groups of three elements each
- Dobereiner was the first to correlate atomic masses with element properties.
- Mass number represents the total count of protons and neutrons in an element.
- The Law of Triads states that the atomic mass of the middle element in a triad is approximately the average of the other two when listed by increasing atomic mass.
- Dobereiner could only identify three triads among the known elements.
- Limitations: Not all known elements could be classified into triads based on their properties, and not all groups obeyed the Law of Triads.
Newlands' Law of Octaves
- In 1866, John Newlands, an English scientist, organized elements by increasing atomic mass.
- Hydrogen was the starting element, having the lowest atomic mass.
- Every eighth element had similar properties, similar to musical octaves.
- Newlands arranged 56 elements into seven groups.
- Fluorine's properties are similar to hydrogen; sodium's to lithium; magnesium's to beryllium.
- Newlands' arrangement was the first to group elements based on a fundamental property like atomic mass.
- Limitations: Applicable only to elements with low atomic masses, specifically up to calcium.
- Newlands assumed only 56 elements existed and did not account for future discoveries.
- Cobalt and nickel's placement was not explained, as they were grouped with elements of different properties.
- Iron, with properties similar to cobalt and nickel, was placed in a different column.
- Newlands' Law of Octaves was not widely accepted due to its limitations.
Lother Meyer's Arrangement
- In 1869, Lother Meyer, a German chemist, plotted physical properties of elements against their atomic weights.
- These properties include atomic volume, density, melting/boiling points, and thermal conductivity
- Elements were arranged based on the periodic variation of these properties, resembling Mendeleev's arrangement.
Mendeleev's Periodic Table
- Dmitri Ivanovich Mendeleev correlated element properties with atomic masses.
- Mendeleev introduced the concept of a periodic table, arranging elements by increasing atomic masses.
- A periodic table consists of vertical columns called groups and horizontal rows called periods
- Mendeleev formulated the periodic law that the properties of elements are a periodic function of their atomic masses.
- The periodic law also holds that elements with similar properties are grouped together
- Mendeleev arranged elements in increasing atomic mass order
- Mendeleev also left gaps for undiscovered elements, predicting their existence and properties, such as "Eka-aluminium" (gallium).
- Mendeleev correctly predicted properties of undiscovered elements
- Mendeleev's table accommodated noble gases without disturbing other elements
- Mendeleev placed some elements with higher atomic masses before those with lower masses to maintain similar property groupings.
- Limitations included the inconsistent placing of hydrogen and the placement of isotopes in different columns.
Modern Periodic Table
- Henry Moseley demonstrated in 1913 atomic number is fundamental for classification rather than atomic mass
- Atomic number = number of protons = number of electrons in a neutral atom.
- The modern periodic law states that the properties of elements are a periodic function of their atomic numbers.
- The modern periodic table arranges elements by increasing atomic number.
- The modern periodic table has elements in rows (periods) and columns (groups), with seven periods and 18 groups.
- Hydrogen is above alkali metals due to electronic configuration similarities but remains a unique element.
- Elements in the same group have the same number of valence electrons.
- The number of electrons in the valence shell increases by one unit moving left to right across a period.
- The maximum number of electrons a shell can hold is calculated using the formula 2n².
- The position of an element indicates reactivity, and valence electrons dictate bond formation.
- The modern periodic table has trends for determining various properties of the elements, such as atomic size and metallic character.
- Valency is the number of electrons an atom requires to lose, gain, or share to attain a noble gas configuration
- Valency first increases and then decreases as you move left to right across a period.
- The valency in a group stays the same
- Atomic size (radius of an atom) increases from top to bottom and decreases left to right across the periodic table.
- Metals lose electrons to form a cation (positive ion): metals are electropositive
- Metallic character decreases from left to right, increases from top to bottom in the modern table.
- Elements on the left form basic oxides, while those form non-metals form acidic oxides.
- Elements show periodicity because of a similar valence shell configuration.
- Properties that show periodicity include atomic radius, ionisation potential, electron affinity, electronegativity, and metallic character.
- Ionization potential is the energy required to remove one mole of electrons from the valence shell of one mole of isolated gaseous atoms
- Electronegativity is the tendancy of an atom of an element to attract a shared pair of electrons towards itself
- Metallic character is the tendency of an atom to lose electrons.
IUPAC Nomenclature
- IUPAC provides a naming system for elements with atomic numbers greater than 100
- Latin roots are used to represent the digits in the atomic number, with "ium" added at the end.
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Periodic table (CLS 10) Chemistry
