Basic Chemistry & Atomic Structure

Basic Chemistry and Atomic Structure

Page 2: Learning Objectives

• Students should be able to:

  • Name the four essential and most abundant elements of life.

  • Describe atomic structure; identify charge and location of protons, neutrons, and electrons.

  • Apply principles of atomic number and mass number.

  • Describe isotopes and radioactive isotopes.

  • Draw electron distribution diagrams for elements in the first three rows of the periodic table.

  • Explain why atoms are reactive.

Page 3: Composition of Life

• Organisms are composed of matter (anything that occupies space and has mass).

• Matter is made up of elements, anything that takes up space and has mass.

• Element is a pure substance that can’t be broken down (carbon, iron, oxygen)

• Atom is basic unit of matter

Page 4: Elements in the Human Body

• Table of Major Elements:

  • Oxygen (O): 65.0% - Essential

  • Carbon (C): 18.5% - Most abundant

  • Hydrogen (H): 9.5%

  • Nitrogen (N): 3.3%

  • Calcium (Ca): 1.5%

  • Phosphorus (P): 1.0%

  • Potassium (K): 0.4% (Trace)

  • Sulfur (S): 0.3% (Trace)

  • Additional trace elements: e.g., Iron (Fe), Iodine (I).

Page 5: Basic Structure of Atoms

• Atoms consist of three types of particles:

  • Protons (+)

  • Neutrons (0)

  • Electrons (-)

• Atomic structure:

  • Protons and neutrons make up the atomic nucleus.

  • Electrons are located in the electron shells (cloud).

  • Protons and neutrons have a mass of approximately 1 dalton; electrons have negligible mass.

Page 6: Atomic Number and Mass Number

• Atomic Number (bottom): The number of protons; defines the element.

• Mass Number (top): Total number of protons and neutrons.

• Note: Atomic mass differs slightly due to isotopic variations.

Page 7: Periodic Table

• The periodic table organizes elements based on atomic structure and properties.

• Familiarize with symbols and atomic weights of elements like:

  • Hydrogen (H): 1.0079

  • Carbon (C): 12.011

  • Nitrogen (N): 14.007

• Nomenclature of elements essential for understanding.

Page 8: Practice Questions

• Identify elements:

  • An atom with 7 protons and 7 neutrons.

  • An atom with 8 protons and mass number of 16; calculate neutrons.

  • An atomic number of 14 and 16 neutrons; find mass number.

Page 9: Isotopes

• Definition: variations of atoms of same element with a different number of neutrons and mass numbers

• Examples include Carbon-12, Carbon-13, and Carbon-14.

• Greek roots: "iso" means equal, "topos" means place.

Page 10: Radioactive Isotopes

• Definition: Unstable isotopes that decay and release particles and energy. (finding an age/how long ago did it die etc)

• Examples: 18F, 11C, 238U, Technetium-99m.

• Applications in medicine as radiotracers or radiation therapy (e.g., PET scans).

Page 11: Electron Configuration

• Electron Shells:

  • First shell: maximum 2 electrons.

  • Second shell and third shell: maximum of 8 electrons.

  • Layout of elements like Hydrogen (H) and Carbon (C).

Page 12: Orbitals

• Orbital: 3D space where electrons are likely to be found; usually contains a maximum of 2 electrons.

  • Structure exemplifies how electrons occupy shells.

Page 13: Rules for Electron Distribution

• Steps to draw electron distribution diagrams:

  1. Draw the nucleus and number of protons.

  2. Place unpaired electrons first, then pair.

  3. Fill inner shells before outer shells.

Page 14: Practice Diagrams

• Practice drawing electron distribution diagrams for elements:

  • Boron (B)

  • Chlorine (Cl)

• Familiarize with the diagrams for various elements.

Page 15: Atomic Reactivity

• Atoms with incomplete outer shells are reactive.

• Valence Electrons: Electrons in the outermost shell.

Page 16: Filling Valence Shells

• Atoms react by accepting, donating, or sharing electrons to achieve full valence shells.

Page 17: Chemical Bonds

• Atoms form chemical bonds when they join together to create molecules and compounds.

Page 18: In-class Exercise

• Experiment with combining hydrogen and oxygen to form water (H2O).

Page 19: Vocabulary Summary

• Key terms to know:

  • Element

  • Proton

  • Electron

  • Neutron

  • Atomic number

  • Mass number

  • Isotope

  • Vocabulary: Radioactive isotope, electron shell, orbital, valence electron, valence shell, chemical bond.