1 / 33

Atomic Structure

Atomic Structure. Topic 1. Objectives:. To understand how the model of the atom has changed To know the subatomic particles and all their properties To understand electrons and their energies To be able to distinguish between ground, excited state and ion configurations

isla
Download Presentation

Atomic Structure

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Atomic Structure Topic 1

  2. Objectives: • To understand how the model of the atom has changed • To know the subatomic particles and all their properties • To understand electrons and their energies • To be able to distinguish between ground, excited state and ion configurations • To distinguish between different types of matter

  3. Early Studies of Matter • The model of the atom is the work of many scientists over a long period of time • Greeks • Fire, air, water, and earth • Boyle – 1600s • Gold and silver are elemental

  4. Dalton – 1700s • Atom = basic unit of matter • cannonball • Dalton’s Atomic Theory • All elements are composed of indivisible atoms • All atoms of a given element are identical • Atoms of different elements are different; (different masses) • Compounds are formed by the combination of atoms of different elements • Not all correct today but the groundwork

  5. Thomson – “Plum Pudding” • Electron • Atom has some negative charged particle found within

  6. Rutherford’s Gold Foil Experiment • Nucleus of atom discovered • Nuclear model • Experiment: • Alpha particle shot at a piece of gold foil

  7. Rutherford’s Gold Foil Experiment

  8. Bohr Model • Planetary model • Electrons in definite fixed orbits • How we draw them

  9. Wave-Mechanical Model • Most modern model of the atom • Gives electrons properties of both particle and wave • Electrons with distinct amounts of energy moving in orbitals • Orbitals = region in which electron is likely to be located

  10. Structure of the Atom • Positive nucleus and negative electrons in regions called orbitals outside nucleus

  11. Atomic Number • Atomic Number is the number of protons Atomic number = # protons • Each element has its own atomic number…it identifies what element you have

  12. Complete Chart

  13. Atom is neutral • Neutral means equal amount of positive and equal amount of negative • SOOO…. WHAT 2 SUBATOMIC PARTICLES WILL BE EQUAL IN AN ATOM? • Remember: APE

  14. Mass Number • Mass number is the mass of the nucleus (protons + neutrons) Mass # = #protons + #neutrons Mass # - #protons = #neutrons • Notation: C-12 126C

  15. Complete Chart

  16. Isotopes • Isotopes are atoms of the same element that have different numbers of neutrons (giving them different mass numbers) • Same: #protons (atomic numbers) • Different: #neutrons (mass numbers)

  17. Atomic Masses • Average masses of all the naturally occurring isotopes • Weighted average

  18. Finding Atomic Mass Problems • Carbon has 2 naturally occurring isotopes. 98.89% of C’s are C-12 with a mass of 12 amu. The remaining 1.108% are C-13 with a mass of 13 amu. What is the atomic mass of carbon?

  19. Sample Problem Element X three isotopes; one that occurs 72.0% with a mass of 84.9 amu, the second that occurs 18.0% with a mass of 87.0 amu, and the last that occurs 10% with a mass of 89.1 amu. Find the average atomic mass of Element X.

  20. Solution

  21. Electrons, Electrons, Electrons • Electrons surround the nucleus in regions called orbitals • Electron Configurations for the atom are on the reference tables • Tells how many electrons are in each energy level • Last number in electron configuration is number of valence electrons (outermost electrons)

  22. Sample Questions • Write the electron configuration of the following atoms: • Sodium • Chlorine • Fe • Circle the valence electrons in the above atoms

  23. Energy of Electrons • Each electron has its own distinct amount of energy that corresponds to the energy level that it occupies • Higher the energy level the higher the electron’s energy

  24. Ground vs. Excited State • Electrons can gain or lose energy making them move to higher or lower energy levels • Ground State: electrons in their normal energy levels; stable • Found on the reference table • Excited State: electron gains energy and moves up to a higher energy level • Start with configuration on table, keep same number electrons, but change the order

  25. Continued • Ground  Excited; energy is __________ • Excited  Ground; energy is __________ • Calcium atom’s electron configuration is… • Ground state: • Excited state:

  26. Sample Problems

  27. Sample Problems • Which shows an increase in energy? A - Electron that goes from the 2nd shell to the 3rd shell B - Electron that goes from the 3rd shell to the 2nd shell • Which of the above A or B will produce a light spectrum?

  28. Ionic Radii

  29. Types of Matter • Matter – anything that has mass and takes up space (volume) • Homogeneous – uniform composition • Can contain more than one type of particle, but the particles have to be evenly mixed • Sugar water • Heterogeneous – varying composition • Parts have there own chem and phys properties • Chocolate chip cookie

  30. Matter Pure Substance Mixtures All other heter. mixs Compound Element Solutions

  31. Definitions • Pure Substances – composition is the same throughout • Element – substances that cannot be broken down or decomposed into simpler substances by chemical means

  32. Compounds – two or more elements that are chemically combined in definite proportions by mass • Law of definite proportions – types of atoms in a compound exist in a fixed ratio • H2O2 vs. H2O • H2O: mass ratio of 1:8

  33. Mixtures – combinations of two or more pure substances that can be separated by physical means (not in “fixed” ratios) • Heterogeneous mixtures • Homogenous mixtures = solutions

More Related