Chemistry Chapter on Atomic Structure and Properties
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Questions and Answers

What defines a salt in solution?

  • They have a significant effect on pH.
  • They disassociate into cations and anions. (correct)
  • They are always organic compounds.
  • They contain H+ or OH- ions.

    • How do buffer systems function in a solution?

  • By increasing the concentration of H+ ions.
  • By forming new compounds with H+ ions.
  • By stabilizing pH through a reversible reaction. (correct)
  • By completely neutralizing acids and bases.

    • Which of the following is NOT a major class of organic compounds?

  • Carbohydrates
  • Lipids
  • Minerals (correct)
  • Nucleic acids

    • Which functional group is specifically associated with amino acids?

    <p>Amino group (-NH2)</p> Signup and view all the answers

    What is the primary characteristic of lipids?

    <p>They are mainly hydrophobic molecules.</p> Signup and view all the answers

    Which of the following statements about carbohydrates is true?

    <p>The ratio of carbon to hydrogen to oxygen is approximately 1:2:1.</p> Signup and view all the answers

    Which polysaccharide is indigestible for humans?

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

    What action must occur for disaccharides to be used by the body?

    <p>They must undergo hydrolysis.</p> Signup and view all the answers

    What term is used to describe nonpolar molecules that do not react with water?

    <p>Hydrophobic molecules</p> Signup and view all the answers

    Which of the following is true about the pH scale?

    <p>A lower pH indicates a higher concentration of hydrogen ions.</p> Signup and view all the answers

    What is the role of hydrogen ions in physiological processes?

    <p>They are essential and very reactive.</p> Signup and view all the answers

    What does an acid release into a solution?

    <p>Hydrogen ions (H+)</p> Signup and view all the answers

    What condition is caused by excessive acidity in body fluids?

    <p>Metabolic acidosis</p> Signup and view all the answers

    What describes a base in terms of hydrogen ions?

    <p>It lowers hydrogen ion concentration.</p> Signup and view all the answers

    Which of the following statements about pH is incorrect?

    <p>A high pH indicates low hydroxide ion concentration.</p> Signup and view all the answers

    What compounds affect acidity in a solution?

    <p>Compounds containing H+ or OH- ions</p> Signup and view all the answers

    What determines an element's mass number?

    <p>The total number of protons and neutrons</p> Signup and view all the answers

    What are isotopes?

    <p>Atoms of the same element with different mass numbers due to differing neutrons</p> Signup and view all the answers

    Which statement is true regarding atoms with equal protons and electrons?

    <p>They have a neutral charge</p> Signup and view all the answers

    What is the significance of a mole (mol) in chemistry?

    <p>It is a quantity equal to the element's atomic weight in grams</p> Signup and view all the answers

    How are electrons arranged within an atom?

    <p>In distinct energy levels or shells</p> Signup and view all the answers

    What happens to an atom when it loses or gains electrons?

    <p>It becomes an ion with a net charge</p> Signup and view all the answers

    Which energy level in an atom can hold a maximum of 2 electrons?

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

    What dictates the chemical properties of an atom?

    <p>The number of electrons in the outermost energy level</p> Signup and view all the answers

    Which type of lipid contains carbon chains that can be saturated, monounsaturated, or polyunsaturated?

    <p>Fatty Acids</p> Signup and view all the answers

    What type of glyceride consists of two fatty acids attached to a glycerol molecule?

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

    Which class of lipids is characterized by having a hydrophilic head and a hydrophobic tail?

    <p>Phospholipids and Glycolipids</p> Signup and view all the answers

    Which lipid acts as a local hormone and is derived from arachidonic acid?

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

    What is the primary structure of steroids?

    <p>Four carbon rings</p> Signup and view all the answers

    Which of the following fatty acid types has no double bonds in its carbon chain?

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

    What molecule is the most abundant class of molecules in the human body, essential for all body functions?

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

    Which types of hormones are classified as steroids?

    <p>Estrogens and testosterone</p> Signup and view all the answers

    Which function of proteins is primarily associated with maintaining the pH balance in the body?

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

    What is the unique shape that a polypeptide must attain to function as a protein?

    <p>A folded structure</p> Signup and view all the answers

    Which component is not part of an amino acid?

    <p>Hydroxyl group</p> Signup and view all the answers

    Which level of protein structure refers to the specific sequence of amino acids?

    <p>Primary structure</p> Signup and view all the answers

    Which type of protein is primarily responsible for facilitating chemical reactions in cells?

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

    What type of bond links amino acids together in a protein?

    <p>Peptide bond</p> Signup and view all the answers

    Which of the following statements about proteins is incorrect?

    <p>Proteins consist only of amino acids.</p> Signup and view all the answers

    Which function of proteins is involved in the response to foreign pathogens in the body?

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

    Study Notes

    Atomic Structure

    • Electrons orbit the nucleus in a spherical electron cloud, constituting the electron shell.
    • Element's mass number = number of protons + number of neutrons in the nucleus.
    • Neutrons carry no charge but contribute significant mass.
    • Isotopes are variants of the same element differing in mass due to neutron count; radioisotopes emit radiation and decay at a specific half-life.

    Chemical Properties and Atoms

    • Atomic weight is crucial for chemical reactions; chemists measure chemicals using atomic weight.
    • A mole (mol) is the quantity of an element whose weight in grams equals its atomic weight.
    • Atoms can be neutral (equal protons and electrons) or ionic (unequal protons/electrons).
    • Energy levels denote specific electron capacity: Level 1 holds 2 electrons; Levels 2 and 3 hold 8 electrons each.

    Water and pH Regulation

    • Water has a neutral pH of 7.0, with equal concentrations of H+ and OH- ions.
    • pH scale ranges:
      • pH < 7 indicates acidity (high H+, low OH-);
      • pH > 7 indicates basicity (low H+, high OH-).
    • pH influences physiological functions; excessive H+ can damage cells and proteins, while excess OH- is rare.

    Acids, Bases, and Salts

    • Acids release H+ ions, lowering pH; thus, they're termed proton donors.
    • Excess acidity leads to acidosis; bases accept H+ ions, raising pH (proton acceptors).
    • Salts consist of cations and anions but do not release H+ or OH- ions, typically not affecting solution pH.

    Buffers

    • Buffers consist of weak acids and bases, stabilizing pH by reacting with H+ ions in a reversible manner, neutralizing strong acids or bases.

    Organic Compounds

    • Organic compounds are large molecules primarily made of carbon, hydrogen, and oxygen.
    • Four major classes: carbohydrates, lipids, proteins, nucleic acids.
    • Functional groups (e.g., carboxyl, amino, hydroxyl, phosphate) allow interaction with other molecules.

    Carbohydrates

    • Composed of a carbon/hydrogen/oxygen ratio of ~1:2:1.
    • Categories include:
      • Monosaccharides: simple sugars (e.g., glucose, fructose).
      • Disaccharides: two simple sugars (e.g., sucrose) formed via dehydration synthesis and broken down by hydrolysis.
      • Polysaccharides: large chains (e.g., cellulose, starch, glycogen) utilized for energy storage and structure.

    Lipids

    • Lipids are hydrophobic molecules (e.g., fats, oils), primarily composed of carbon and hydrogen.
    • Five main classes include fatty acids, eicosanoids, glycerides, steroids, and phospholipids.
      • Fatty acids can be saturated, monounsaturated, or polyunsaturated.
      • Eicosanoids: signaling molecules derived from arachidonic acid.
      • Glycerides consist of varying numbers of fatty acids for energy, insulation, and protection.
      • Steroids have a four-ring structure; key examples include cholesterol and sex hormones.
      • Phospholipids form cell membranes due to hydrophilic heads and hydrophobic tails.

    Proteins

    • Composed mainly of carbon, hydrogen, oxygen, and nitrogen; essential for all body functions.
    • Seven major functions include support, movement, transport, buffering, metabolic regulation, coordination, and defense.
    • Building blocks: amino acids (with central carbon, hydrogen, amino group, carboxylic acid group, and variable side chain).
    • Peptide bonds form between amino acids to create polypeptides; proteins require specific folding to function.
    • Protein structure levels: primary (amino acid sequence), secondary (hydrogen bonds), tertiary (3D folding), quaternary (multiple chains).

    Nucleic Acids

    • Large organic molecules made of carbon, hydrogen, oxygen, nitrogen, and phosphorus, responsible for storage and processing molecular information.

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    Description

    Test your knowledge on atomic structure, chemical properties, and the importance of water and pH regulation in chemistry. This quiz covers essential concepts such as electron configuration, isotopes, atomic weight, and the pH scale. Perfect for students looking to solidify their understanding of these fundamental topics.

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