Atomic Structure and Electronic Configuration
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Questions and Answers

Across a period, the effective nuclear charge increases due to an increase in the number of protons.

True (A)

Which of the following factors contributes to a decrease in ionization energy down a group?

  • Increased shielding effect (correct)
  • Increased number of protons
  • Increased nuclear charge
  • Decreased atomic radius

    • Explain why the ionization energy of aluminum (Al) is lower than that of magnesium (Mg).

    The electron removed in aluminum is from the 3p orbital, which is higher in energy and further from the nucleus than the 3s electron removed from magnesium.

    The ______ effect is the repulsion experienced by outer electrons due to the presence of inner electrons.

    <p>shielding</p> Signup and view all the answers

    Match the following trends to their corresponding effect on ionization energy.

    <p>Increased nuclear charge = Increases ionization energy Increased shielding effect = Decreases ionization energy Decreased atomic radius = Increases ionization energy Increased distance from the nucleus = Decreases ionization energy</p> Signup and view all the answers

    What distinguishes isotopes from one another?

    <p>Different numbers of neutrons (B)</p> Signup and view all the answers

    Isotopes of an element exhibit different chemical properties.

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

    What causes the different physical properties of isotopes?

    <p>Different masses due to different numbers of neutrons.</p> Signup and view all the answers

    Each orbital can hold __ e-s, which must have opposite spins.

    <p>2</p> Signup and view all the answers

    When electrons occupy orbitals of equal energy, what must they do?

    <p>Occupy singly before pairing (B)</p> Signup and view all the answers

    Match the following concepts related to electron configurations:

    <p>Completely filled orbitals = More stable due to reduced repulsion Half-filled orbitals = More stable due to reduced repulsion 4s electrons = Promoted to stabilize 3d orbitals 3d orbitals = Filled after 4s during removal</p> Signup and view all the answers

    Filling 3d orbitals occurs before filling 4s orbitals.

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

    What effect does promoting an electron from 4s to 3d have on an atom's stability?

    <p>It increases stability by allowing for half-filled or completely filled 3d orbitals.</p> Signup and view all the answers

    Which of these statements accurately describes the trend of ionization energy across a period?

    <p>Ionization energy generally increases from left to right. (B)</p> Signup and view all the answers

    The ionic radius of a negative ion is always smaller than the ionic radius of a positive ion in the same period.

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

    Explain why the ionization energy of sulfur is lower than that of phosphorus.

    <p>Sulfur has a more filled 3p orbital, resulting in increased electron-electron repulsion. This repulsion weakens the hold of the nucleus on the outermost electron, making it easier to remove, hence a lower ionization energy.</p> Signup and view all the answers

    The ______ of an atom is a measure of its size, which generally increases as you move down a group.

    <p>atomic radius</p> Signup and view all the answers

    Match the following trends with their correct explanation:

    <p>Ionization energy increases across a period = Increased nuclear charge and less effective shielding. Ionic radius decreases across a period = Increased nuclear charge with constant number of electron shells. Ionic radius decreases down a group = Decreased effective nuclear charge due to shielding. Ionic radius increases down a group = Increased number of electron shells.</p> Signup and view all the answers

    Which of the following factors contributes to lower ionization energy?

    <p>Increased electron-electron repulsion (A)</p> Signup and view all the answers

    Elements with completely or half-filled orbitals tend to have lower ionization energies.

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

    Why are negative ions generally larger than positive ions in the same period?

    <p>Negative ions have gained electrons, increasing the number of electrons while the nuclear charge remains constant. This leads to increased repulsion between the electrons, expanding the electron cloud and increasing the ionic radius.</p> Signup and view all the answers

    Which subatomic particle has a negative charge?

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

    Neutrons are deflected in an electric field due to their neutral charge.

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

    What is the atomic mass of a neutron in atomic mass units (a.m.u)?

    <p>1</p> Signup and view all the answers

    The maximum probability of finding an electron is located in a region called the ______.

    <p>orbital</p> Signup and view all the answers

    Match the subatomic particles with their corresponding charge:

    <p>Proton = Positive charge Neutron = No charge Electron = Negative charge</p> Signup and view all the answers

    What happens to the number of electrons lost as the positive charge on the cation increases?

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

    As the positive charge on the cation increases, the electrostatic attraction between the nucleus and outer electrons decreases.

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

    What effect does the increase of cation charge have on electrostatic attraction?

    <p>It increases the electrostatic attraction.</p> Signup and view all the answers

    As the positive charge on the cation increases, the number of electrons lost ______.

    <p>increases</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Cation = A positively charged ion Electrostatic attraction = The force that draws opposite charges together Outer electrons = Electrons in the outermost shell of an atom Nucleus = The central part of an atom containing protons and neutrons</p> Signup and view all the answers

    Which orbital is filled before the 3d orbital in period 3 elements?

    <p>4s (B)</p> Signup and view all the answers

    Electrons in the 4s orbital are lost before those in the 3d orbital when forming cations.

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

    What is the shape of p orbitals?

    <p>Dumbbell-shaped</p> Signup and view all the answers

    The __________ principle describes the order in which atomic orbitals are filled.

    <p>Aufbau</p> Signup and view all the answers

    Match the electron configurations with their maximum electrons:

    <p>s = 2 p = 6 d = 10 f = 14</p> Signup and view all the answers

    What occurs during each successive ionization energy?

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

    A free radical has all its electrons paired.

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

    Define a free radical.

    <p>A species with one or more unpaired electrons.</p> Signup and view all the answers

    Study Notes

    Atomic Structure

    • Subatomic particles include protons, neutrons, and electrons
    • Protons have a positive charge and a mass of 1 amu
    • Neutrons have no charge and a mass of 1 amu
    • Electrons have a negative charge and a mass of 1/1840 amu
    • Atomic number (Z) equals the number of protons
    • Atomic mass (A) equals the sum of protons and neutrons
    • Isoelectronic ions have the same number of electrons
    • Isotopes are atoms of the same element with different numbers of neutrons
    • Isotopes have similar chemical properties, but different physical properties
    • Electrons are arranged in energy levels (shells) with increasing energy as shell number increases.
    • Each shell can hold a maximum number of electrons
    • Within shells, electrons are in orbitals (s, p, d, f)
    • Each orbital can hold a maximum of two electrons (with opposite spins),
    • Orbitals are filled in order of increasing energy based on Aufbau's principle.

    Electronic Configuration

    • Electrons fill orbitals in a specific order to achieve the lowest possible energy arrangement (Aufbau Principle)
    • 1s, 2s, 2p, 3s, 3p... represents order of energy levels - s orbitals are spherical; p orbitals are dumbbell-shaped.
    • Electrons fill subshells in order of increasing energy until all are filled
    • Electron configuration can be represented as a shorthand notation using superscripts
    • Example: Lithium (Li) 1s22s1

    Orbitals

    • Orbitals are regions in space where there is a high probability of finding an electron

    Subshells

    • Subshells (s, p, d, f) are groups of orbitals with the same energy level
    • Each subshell can hold a specific maximum number of electrons

    Ionization Energies

    • Ionization energy is the energy required to remove an electron from an atom or ion in the gaseous state.
    • First ionization energy is the energy needed to remove the first electron
    • Successive ionization energies increase as more electrons are removed, due to increased nuclear charge & reduced shielding.

    Factors Affecting Ionization Energy

    • Nuclear charge (greater charge = higher ionization energy)
    • Shielding effect (more electron shells = lower ionization energy)
    • Atomic radius (larger radius = lower ionization energy)
    • Stable configurations- completely or half-filled orbitals have high ionization energies
    • Ionization energy generally increases across a period due to increased nuclear charge and decreased shielding effects.
    • Ionization energy generally decreases down a group due to increased atomic radius and increased shielding effects.

    Ionic Radius

    • Ionic radius is a measure of the size of an ion.
    • Positive ions (cations) are smaller than their neutral atom counterparts due to loss of electrons and reduced shielding.
    • Negative ions (anions) are larger than their neutral atom counterparts due to increased electron.

    Positive and Negative Ions

    • Positive ions (cations) are formed by losing electrons
    • Negative ions (anions) are formed by gaining electrons
    • Size of positive ions are smaller than the original atom
    • Size of negative ions are larger than the original atom

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    Description

    This quiz covers fundamental concepts of atomic structure, including subatomic particles, atomic number and mass, isotopes, and electron configuration. Explore how electrons are arranged in energy levels and the principles governing their filling in orbitals. Test your understanding of these essential topics in chemistry.

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