Trends in the Periodic Table
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Questions and Answers

What occurs to electron affinity as one progresses from left to right across a period?

  • It remains constant.
  • It increases. (correct)
  • It decreases.
  • It becomes unpredictable.

How does electronegativity change as you move down a group?

  • It remains unchanged.
  • It increases significantly.
  • It decreases. (correct)
  • It fluctuates in a random manner.

Which of the following is NOT a metallic property?

  • Displacement of hydrogen in acids
  • Formation of ionic chlorides
  • Formation of covalent bonds (correct)
  • Formation of cations

What effect does atomic radius have on electron affinity when moving down a group?

<p>It decreases electron affinity. (D)</p> Signup and view all the answers

The ability of an atom to attract pairs of electrons in a chemical bond is known as what?

<p>Electronegativity (B)</p> Signup and view all the answers

What role does nuclear charge play in the attraction of electrons to the nucleus?

<p>It increases the attraction as protons are added to the nucleus. (B)</p> Signup and view all the answers

Which factor is primarily responsible for the different sizes of atoms in the periodic table?

<p>Quantum theory related energy levels. (D)</p> Signup and view all the answers

What is the effect of electron shielding on the electrons in an atom?

<p>It pushes electrons in upper levels further from the nucleus. (A)</p> Signup and view all the answers

How does quantum theory contribute to our understanding of electron arrangement?

<p>It indicates specific distances of electrons from the nucleus based on energy levels. (C)</p> Signup and view all the answers

What consequence does increased electron repulsion have within the same energy level?

<p>It pushes electrons further away from each other. (D)</p> Signup and view all the answers

Which element has a greater atomic radius?

<p>Potassium (K) (A)</p> Signup and view all the answers

What trend is observed in atomic radii as you move across a period from left to right?

<p>Atomic radii decrease (B)</p> Signup and view all the answers

Why do atomic radii increase down a group?

<p>There are more filled inner energy levels (A)</p> Signup and view all the answers

Which statement is true about the reactivity of non-metals compared to metals?

<p>Reactivity of non-metals typically decreases down a group (D)</p> Signup and view all the answers

What factor contributes to the atomic radius changes across a period?

<p>Stronger nuclear attraction to valence electrons (D)</p> Signup and view all the answers

Which of the following elements would likely have the largest atomic radius?

<p>Rubidium (Rb) (D)</p> Signup and view all the answers

What describes the reactivity of noble gases?

<p>They are essentially non-reactive (A)</p> Signup and view all the answers

In periodic trends, how does the strength of attraction between the nucleus and valence electrons change across a period?

<p>It increases (D)</p> Signup and view all the answers

How does the shielding effect influence the atomic radius?

<p>It allows the outer shell to experience less nuclear pull. (D)</p> Signup and view all the answers

What happens to the ionic radius when a neutral atom forms a positive ion?

<p>The ionic radius decreases as electrons are removed. (A)</p> Signup and view all the answers

Why does ionic radius increase down a group?

<p>The outermost occupied energy level moves further from the nucleus. (D)</p> Signup and view all the answers

What trend is observed in ionic radii for positive ions as one moves across a period?

<p>Ionic radii decrease due to increased nuclear attraction. (C)</p> Signup and view all the answers

What defines the first ionization energy?

<p>Energy to remove the most weakly held electron from a neutral atom. (D)</p> Signup and view all the answers

How do ionization energies change across a period and why?

<p>They increase due to a greater number of protons attracting electrons more strongly. (D)</p> Signup and view all the answers

What effect does gaining an electron have on an atom?

<p>It increases the radius due to a greater electron cloud. (D)</p> Signup and view all the answers

What trend is observed regarding ionization energy as you move down a group?

<p>Ionization energy decreases due to weaker attraction of valence electrons to the nucleus. (D)</p> Signup and view all the answers

Flashcards

Reactivity

The tendency of an element to gain or lose electrons in chemical reactions. It increases down a group and decreases across a period.

Atomic Radius

The distance between the nucleus of an atom and its outermost electron shell. It decreases across a period and increases down a group.

Nuclear Attraction

The strength of the attraction between the positively charged nucleus and the negatively charged valence electrons.

Energy Levels

The number of electron shells (energy levels) surrounding the nucleus of an atom.

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Valence Electrons

The electrons in the outermost energy level of an atom. They are involved in chemical bonding.

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Group (Periodic Table)

A group of elements located in the same vertical column of the periodic table. They share similar chemical properties.

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Period (Periodic Table)

A row of elements located in the same horizontal row of the periodic table. Elements in a period have a varying number of electron shells.

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Noble Gases

Elements that are generally unreactive due to having a full outer shell of electrons.

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Electron Affinity

The energy required to add an electron to a neutral atom in its gaseous state, forming a negative ion. It is considered a measure of an atom's tendency to gain an electron.

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Electronegativity

The ability of an atom in a molecule to attract shared electrons towards itself.

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First Ionization Energy

The energy needed to remove one electron from a neutral atom in its gaseous state, forming a positively charged ion.

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Metallic Properties

The ability of an element to lose electrons and display metallic properties, such as forming cations, reacting with acids, and forming basic oxides and ionic chlorides.

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What does Bohr's model explain about electrons and their influence on trends in the periodic table?

Bohr's model explains that electrons exist in specific energy levels at varying distances from the nucleus. This leads to differences in atomic size and electrostatic forces due to varying electron distances.

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Explain how nuclear charge influences the trends in the periodic table.

As more protons are added to the nucleus, the positive charge increases, resulting in a stronger electrostatic attraction for the surrounding electrons. This pull makes the electrons closer to the nucleus.

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How does electron shielding affect electron positions in the periodic table?

Electrons within lower energy levels create a negative shield that repels electrons in higher energy levels, pushing them further away from the nucleus. This effect weakens the attraction of the nucleus on the outer electrons.

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How do the factors of shielding and nuclear charge explain trends in the periodic table?

The influence of electron shielding and nuclear charge on electron distances from the nucleus gives rise to trends in the periodic table. These trends explain how elements behave in chemical reactions.

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What are some key trends observed in the periodic table?

Atomic size, ionization energy, electron affinity, and electronegativity are some key trends observed in the periodic table that arise due to the combined effect of electron shielding and nuclear charge.

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Shielding Effect

The increasing number of inner energy levels in atoms leads to greater shielding of the outermost electrons.

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Cation

A positively charged ion formed by the loss of electrons. They have a smaller radius than their neutral atom counterparts.

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Ionic radius trend across a period (cations)

The ionic radius of cations decreases as you move across a period (left to right). This is because the increasing nuclear attraction pulls electrons closer to the nucleus.

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Ionic radius trend down a group (cations)

The ionic radius of cations generally increases down a group. This is because the outermost occupied energy level is farther from the nucleus, leading to less nuclear attraction.

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Anion

A negatively charged ion formed by the gain of electrons. They have a larger radius than their neutral atom counterparts.

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Ionization Energy

The energy required to remove an electron from an atom or ion in the gaseous state. The first ionization energy refers to removing the most loosely bound electron.

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Trend of Ionization energy across a period

Across a period (left to right), ionization energy increases. This is because the increasing nuclear charge holds electrons more tightly, making it more difficult to remove them.

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Study Notes

  • Three factors contribute to periodic trends: quantum theory, nuclear charge, and electron shielding.

Quantum Theory

  • Bohr's atomic model suggests electrons orbit the nucleus at specific energy levels and distances.
  • This results in varying sizes and electrostatic forces between electrons and the nucleus.
  • Electrons are positioned at a specific distance from the nucleus.

Nuclear Charge

  • As more protons are added to the nucleus, the electrostatic attraction between the nucleus and the orbiting electrons increases.
  • The increased nuclear charge leads to stronger attraction of electrons within the same energy level.
  • This pulls electrons closer to the nucleus.

Electron Shielding

  • Electrons experience repelling forces from other electrons.
  • Electrons in lower energy levels shield those in higher levels, pushing them further from the nucleus.
  • Increased electron population within energy levels enhances repulsion, further pushing electrons away from the nucleus.

Reactivity

  • Reactivity is dependent on atomic structure.
  • The noble gases are largely non-reactive.
  • Reactivity in non-metals increases to the right.
  • Reactivity in metals increases down.

Atomic Radius (Across a Period)

  • Atomic radii generally decrease from left to right across a period.
  • The attraction between the nucleus and valence electrons increases as protons are added, pulling the electrons closer.
  • The number of filled inner energy levels remains the same.

Atomic Radius (Down a Group)

  • Atomic radii generally increase down a group.
  • The more inner energy levels, the more shielded the valence electrons become, and less pulled towards the nucleus, leading to an increase in atomic radius.

Ionic Radius (Positive Ions)

  • Removal of electrons forms cations.
  • Cations have a smaller radius than the original neutral atom.
  • Ionic radii increase down a group, due to the outermost occupied electron energy level being further from the nucleus.
  • Ionic radii decrease across a period as nuclear attraction to electrons increases.

Ionic Radius (Negative Ions)

  • Gaining electrons forms anions.
  • Anions have a larger radius than the original atom.
  • Anions have increased repulsion of electrons leading to a larger radius.

Ionization Energy

  • Ionization energy is needed to remove an electron from an atom or ion in the gaseous state.
  • It is not consistent, as the electron being removed varies.
  • First ionization energy is the energy to remove the least bound electron.
  • Second ionization energy is removing an electron from the positively charged ion.
  • Ionization energies increase across a period and generally decrease down a group.

Electron Affinity

  • Electron affinity is the energy change when an electron is added to an atom.
  • It is a measure of how strongly an atom attracts electrons.
  • This results in the formation of an anion if the added electron produces a stable atom.
  • Electron affinities generally increase across a period and decrease down a group.

Electronegativity

  • Electronegativity measures an atom's ability to attract electrons in a chemical bond.
  • Bond type is largely dictated by electronegativity differences between atoms.
  • Electronegativity increases across a period and decreases down a group.

Metallic Properties

  • Metallic properties result from the element's ability to lose electrons.
  • Cations form, hydrogen is displaced in acids, basic oxides form, and ionic chlorides form, etc.

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Periodic Table Trends PDF

Description

This quiz covers the key factors influencing periodic trends in the periodic table, including quantum theory, nuclear charge, and electron shielding. Understand how these concepts affect atomic structure and electron behavior. Test your knowledge on these fundamental principles of chemistry!

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