1 / 24

The Atom

The Atom. Two major parts of an atom. Nucleus (not to scale). Electron Cloud. Three Major Sub-Atomic Particles. Protons Neutrons Electrons. p +. THE PROTON. Heavy = 1 amu Positive + 1 charge Location: Nucleus. . N °. THE NEUTRON. Heavy = 1 amu

hakeem-campbell
Télécharger la présentation

The Atom

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. The Atom

  2. Two major parts of an atom Nucleus (not to scale) Electron Cloud

  3. Three Major Sub-Atomic Particles • Protons • Neutrons • Electrons

  4. p+ THE PROTON • Heavy = 1 amu • Positive + 1 charge • Location: Nucleus

  5. N° THE NEUTRON • Heavy = 1 amu • No charge, neutral • Location: Nucleus

  6. e- THE ELECTRON • Very light = 1/2000 amu • Negative  -1 charge • Location: electron cloud

  7. Where are they located? Nucleus:Protons and Neutrons Electron Cloud:Only Electrons

  8. ATOMIC NUMBER (Z) • The # of protons in an atom • Can not change for an element • All atoms are neutral, so Z equals the # of electrons • For an ion – the number of electrons may differ

  9. Example: Sodium Atomic # = # of protons 11 Na

  10. MASS NUMBER (A) • The mass of an atom • A = protons + neutrons • To determine # of neutrons • Neutrons = A - Z

  11. Example • An atom of sodium has a mass of 24 amu, how many protons, electrons and neutrons does it have? 11 p+ 11 e- 24 - 11 = 13 N° 11 Na

  12. ISOTOPES • Atoms of the same element that differ in mass.(They have the same # of p+, but different # of N°)

  13. Isotope Notation Mass # Atomic #

  14. Isotope Notation • Can also be written as ELEMENT – MASS # • Example: Carbon - 12

  15. So, why do the elements on the PT have masses with decimals???

  16. AVERAGE ATOMIC MASS • The weighted average mass of all naturally occurring isotopes of an element.

  17. Example using exam scores! Exam Scores can be weighted higher than homework or quiz grades: What if… And you received: Exam 50% Exam 93 Quizzes 20% Quizzes 82.5 Homework 30% Homework 85 Your grade = (93 x .5) + (82.5 x .2) + (85 x .3) = 88.5

  18. Example • Example: The element hydrogen has three isotopes. It exists in nature 99.41% of the time as Hydrogen-1, 0.4% of the time as Hydrogen-2 and 0.19% of the time as Hydrogen – 3. What is the average atomic mass of hydrogen? 0.9995*1 + 0.004*2 + 0.001*3 = 1.0078 u

  19. Famous Scientists in Atomic Theory

  20. Democritus (400 B.C.) • First to develop the idea of an atom.

  21. DALTON • Dalton created an atomic theory that stated: • All elements are composed of tiny indivisible particles called atoms • Atoms of the same element are identical. The atoms of any one element are different from those of any other element

  22. J.J. Thomson • “Plum Pudding Model” • Solid positively charged sphere • Electrons embedded within

  23. Rutherford’s Gold Foil Experiment

  24. Rutherford • Proved the existence of a tiny, dense, positively charged nucleus. • The rest of the atom is mostly empty space.

More Related