Atomic Structure Quiz
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Questions and Answers

What term describes the smallest constituent of matter?

  • Proton
  • Atom (correct)
  • Molecule
  • Nucleus

    • Which of the following particles has a negative electric charge?

  • Electron (correct)
  • Proton
  • Neutron
  • Nucleon

    • What is the maximum number of electrons an orbital can hold?

  • One
  • Two (correct)
  • Eight
  • Four

    • What is formed when an atom has more or fewer electrons than protons?

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

    In the atomic structure, what constitutes the nucleus?

    <p>Protons and neutrons</p> Signup and view all the answers

    Which term refers to electrons located in the outermost shell of an atom?

    <p>Valence electrons</p> Signup and view all the answers

    Which of these particles is most associated with atomic mass?

    <p>Both protons and neutrons</p> Signup and view all the answers

    How are orbitals grouped in the context of atomic structure?

    <p>By number</p> Signup and view all the answers

    What is the molar mass of NaCl based on its constituent atomic masses?

    <p>58 g/mol</p> Signup and view all the answers

    In a chemical reaction A + B → AB, which terms are considered reactants?

    <p>A and B</p> Signup and view all the answers

    What is the molar mass of glucose (C6H12O6)?

    <p>180 g/mol</p> Signup and view all the answers

    When calculating molar mass, which of the following elements would contribute 32 g/mol in O2?

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

    What does the chemical equation represent in a reaction?

    <p>The transformation of reactants into products</p> Signup and view all the answers

    How is the molar mass of water (H2O) calculated?

    <p>(2×1) + (1×16)</p> Signup and view all the answers

    What do chemists use to derive the atomic masses used in calculating molar mass?

    <p>Periodic table</p> Signup and view all the answers

    Which type of elements tend to gain electrons and form anions?

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

    What defines the properties of metalloids?

    <p>They exhibit properties of both metals and nonmetals</p> Signup and view all the answers

    Which group of elements is characterized as very reactive nonmetals often found as salts?

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

    Which element belongs to the alkali metals group?

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

    How do alkaline earth metals react with water compared to alkali metals?

    <p>They react fairly vigorously, but not as much as alkali metals</p> Signup and view all the answers

    Which statement about noble gases is accurate?

    <p>They are generally unreactive and inert</p> Signup and view all the answers

    What is a common property of nonmetals in solid state?

    <p>They are brittle</p> Signup and view all the answers

    What percentage of elements in the periodic table are classified as metals?

    <p>75%</p> Signup and view all the answers

    Which group includes elements that are known for their semiconductor properties?

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

    What is the number of neutrons in a Cu atom?

    <p>36</p> Signup and view all the answers

    Which of the following describes a cation?

    <p>An atom with more protons than electrons</p> Signup and view all the answers

    Which statement is correct regarding molecules?

    <p>Molecules are electrically neutral groups of atoms</p> Signup and view all the answers

    How many protons are present in the isotope U-240?

    <p>92</p> Signup and view all the answers

    What is the charge of a magnesium ion (Mg2+)?

    <p>Positively charged</p> Signup and view all the answers

    In the formation of F– ion, how many electrons does the fluorine atom gain?

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

    Which of the following best distinguishes ions from molecules?

    <p>Ions have distinct charges; molecules do not</p> Signup and view all the answers

    Which option describes a property of anions?

    <p>They are negatively charged</p> Signup and view all the answers

    What type of molecule is O2 considered?

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

    How would you classify the reaction Mg → Mg2+ + 2 e–?

    <p>Oxidation reaction</p> Signup and view all the answers

    What is true about atoms of different elements?

    <p>They vary in size and mass.</p> Signup and view all the answers

    Which statement correctly describes isotopes?

    <p>Isotopes of an element differ in mass number.</p> Signup and view all the answers

    What does the atomic number represent?

    <p>The number of protons in the nucleus of an atom.</p> Signup and view all the answers

    What characterizes a neutral atom?

    <p>It has equal numbers of protons and electrons.</p> Signup and view all the answers

    How are isotopes identified?

    <p>By their mass numbers.</p> Signup and view all the answers

    How can one differentiate between isotopes of carbon?

    <p>By their atomic mass.</p> Signup and view all the answers

    What does a chemical reaction entail regarding atoms?

    <p>Rearrangement of existing atoms.</p> Signup and view all the answers

    Which statement about elements and the periodic table is correct?

    <p>Elements have unique atomic numbers.</p> Signup and view all the answers

    What defines a molecule in chemistry?

    <p>A simple whole-number ratio of combined elements.</p> Signup and view all the answers

    Which of the following elements has 29 protons?

    <p>Copper (Cu)</p> Signup and view all the answers

    Study Notes

    Atomic Structure

    • Atoms are the smallest constituent of matter.
    • The word "atom" comes from the ancient Greek adjective "atomos," meaning "indivisible."
    • Atoms are divisible, consisting of a nucleus and surrounding electrons.
    • The nucleus is composed of protons and neutrons.
    • Protons have a positive electric charge and neutrons are electrically neutral.
    • Electrons have a negative electric charge.
    • The number of protons determines the identity of an element.
    • The number of protons (atomic number, Z) and neutrons (N) define the mass number (A).

    Nucleons

    • Protons and neutrons are collectively called nucleons.
    • More than 99.94% of an atom's mass is contained within the nucleus.

    Atomic Charge

    • If the number of protons and electrons are equal, the atom is electrically neutral.
    • If an atom has more or fewer electrons than protons, it's an ion with an overall net charge.

    Electrons in Atoms

    • Electrons are arranged in orbitals (s, p, d, and f).
    • An orbital holds a maximum of two electrons.
    • Orbitals are grouped into shells (1, 2, 3, and so on).

    Modern Atomic Theory and Laws

    • The theory that all matter is composed of atoms originated from several observations and laws.
    • The three primary laws are:
      • Law of conservation of mass
      • Law of definite proportions
      • Law of multiple proportions

    Law of Conservation of Mass

    • Matter is neither created nor destroyed in a chemical reaction.
    • The total mass of reactants equals the total mass of products.

    Law of Definite Proportions

    • A given chemical compound always contains the same elements in exactly the same proportions (by mass), regardless of its source or how it was prepared.

    Law of Multiple Proportions

    • When two elements "combine" to form more than one compound, the ratios of the masses of one element that combine with a fixed mass of the other element are ratios of small whole numbers.

    Dalton's Atomic Theory

    • Each element is composed of tiny, indestructible particles called atoms.
    • An element's atoms are identical in size, mass, and properties.
    • Atoms of different elements vary in size and mass.
    • Atoms of one element cannot change into atoms of another element.
    • Atoms are indivisible and the chemical reaction leads to rearrangement of atoms not to their creation or destruction.
    • Molecules are simple whole-number ratios of combined elements.

    Elements: Defined by their Number of Protons

    • Each element has a unique name, symbol, and atomic number.
    • The symbol for an element usually consists of one or two letters.
    • Elements in the periodic table are arranged in order of increasing atomic number.

    Isotopes

    • Isotopes are atoms of one element that have the same number of protons (atomic number) and different numbers of neutrons.
    • Isotopes differ in mass number but are chemically identical.

    Molecules

    • Molecules are neutrally charged species that contain two or more atoms held together by chemical bonds.
    • Molecules are distinguished from ions by their lack of electrical charge.
    • A molecule may be homonuclear or heteronuclear.

    Ions: Charged Atoms

    • Cations form when an atom loses one or more electrons, and they carry a positive charge.
    • Anions form when an atom gains one or more electrons, and they carry a negative charge.

    Ions: Zwitter Ion

    • A Zwitter ion (also called a dipolar ion) is a neutral molecule that contains both positive and negative charges.

    The Modern Periodic Table

    • Arranged in order of increasing atomic number.
    • Organised into periods (rows) and groups (columns).
    • Similar physical and chemical properties within groups.

    Classification of Elements

    • Metals: Good conductors of heat and electricity, generally solids at room temperature, except mercury, often shiny.
    • Nonmetals: Poor conductors of heat and electricity, some are gases at room temperature.
    • Metalloids: Have properties of both metals and nonmetals (e.g. Semiconductors).

    Major Families

    • Alkali Metals (Group 1A): Highly reactive metals
    • Alkaline Earth Metals (Group 2A): Fairly reactive metals.
    • Halogens (Group 7A): Highly reactive nonmetals.
    • Noble Gases (Group 8A): Mostly unreactive (inert) gases.

    Chemical Formulas and Molecular Models

    • Compound: Distinct substance composed of two or more elements.
    • Chemical formula: Represents the type and number of each element in a molecule.

    Types of Different Formulas

    • Empirical formula: Simplest whole-number ratio of elements.
    • Molecular formula: Actual number of atoms of each element.
    • Structural formula: Diagram of how atoms are bonded together.

    Atomic Level View of Elements and Compounds

    • Atomic elements: Single atoms as particles (e.g., Fe, Na, Al).
    • Molecular elements: Multi-atom molecules (e.g., H₂, O₂, N₂).
    • Molecular compounds: Nonmetal atoms combined (e.g., H₂O, NH₃).
    • Ionic compounds: Metal and nonmetal atoms combined (e.g., NaCl).

    Molecular Elements

    • Certain elements exist as diatomic molecules (7 out of 118 elements in the periodic table): H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂.
    • Some other elements exist as polyatomic molecules (e.g., P₄, S₈, etc.).

    Chemical Reactions

    • A process that transforms one set of chemical substances into another.
    • Reactants are the initial substances involved; products are the resulting substances.
    • Chemical reactions are summarized by chemical equations.

    Chemical Equations

    • Chemical equations are shorthand representations of chemical reactions.
    • The equations include formulas for reactants and products, states (e.g., (g) for gas, (l) for liquid, (s) for solid, (aq) for aqueous) and sometimes energy symbols (e.g. heat).

    Balancing Chemical Equations

    • To show the reaction obeys the Law of Conservation of Mass, the equation must be balanced.
    • The number of each type of atom must be equal on both sides of the equation.

    Types of Chemical Equations

    • Molecular equations: Compounds are written as they exist (as molecules).
    • Ionic equations: Strong electrolytes are written as ions.
      • Net ionic equations: Show only the species involved in the reaction (leaving out spectator ions).

    Chemical Bonds

    • Compounds are formed from bonded atoms.
    • Chemical bonds are attractive forces between atoms.
    • Bonds arise from attraction between protons and electrons of bonded atoms.
    • Bonds can exist between atoms of the same element or between atoms of different elements.
    • Chemical bond formation lowers potential energy.

    Types of Chemical Bonds

    • Ionic bond: Transferring of electrons (metal-nonmetal)
    • Covalent bond: Sharing of electrons (nonmetal-nonmetal)
    • Metallic bond: Pooling of valence electrons

    Representing Valence Electrons with Dots (Lewis Structures)

    • Lewis structures are diagrams visualizing valence electrons using dots around an element's symbol.
    • Main-group element valence electrons equal its group number in the periodic table (except He).
    • Dots are placed singly around the symbol before pairing up (except He).

    Intermolecular Forces

    • Attractive forces between molecules.
    • Weaker than intramolecular forces (bonds).
    • Influence properties such as boiling point, melting point, solubility.
    • Types include London dispersion forces, dipole-dipole interactions, and hydrogen bonding.

    Electronegativity and Bond Polarity

    • Electronegativity: Atom's ability to attract bonding electrons.
    • Higher for nonmetals, lower for metals.
    • Difference in electronegativity (ΔEN) affects bond polarity.
    • Polar bonds have partial charges (δ+ and δ-).

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    Description

    Test your knowledge about atomic structure with this quiz. Explore key concepts such as particles, charges, orbitals, and the nucleus of an atom. Perfect for students studying chemistry or physics.

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