Do Now:Strong Force:

Do Now #_____ What is the strong force and why don't you think it holds the nucleus of larger atoms together as well as smaller atoms?




This video has a nice explanation of why the strong force can't hold larger atoms together as well as smaller atoms hence causing radioactive elements. Watch from 3:49 seconds on or just watch the whole thing.

Half Life - From Wikipedia -

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In general, the half-life of a nuclide depends solely on its nuclear properties; it is not affected by external factors such as temperature, pressure, chemical environment, or presence of a magnetic or electric field.[3][4][5] (For some nuclides which decay by the process of electron capture, such as beryllium-7, strontium-85, and zirconium-89, the decay rate may be slightly affected by local electron density, therefore these isotopes may not be as suitable for radiometric dating.) But in general, the half-life of any nuclide is essentially a constant. Therefore, in any material containing a radioactive nuclide, the proportion of the original nuclide to its decay product(s) changes in a predictable way as the original nuclide decays over time. This predictability allows the relative abundances of related nuclides to be used as a clock to measure the time from the incorporation of the original nuclide(s) into a material to the present.

IONS

Do Now# _____ Define Ion and then draw an ion of helium. Clearly label your protons, neutrons and electrons.

Do Now # ___

Define: Atomic number, mass number and isotope and then draw an isotope of Carbon. (Clearly label your protons, neutrons and electrons.)

Stephen Hawkings - Aliens - Into the Universe

Chapter 12 vocabulary

Atoms

Model

Theory

Nucleus

Electrons

Electron cloud

Protons,

atomoic mass unit (amu)

Nuetrons

Atomic number

Isotopes

Mass number

Atomic mass

Forces in atoms

·         Gravity

·         Electromagnetic force

·         Strong force

·         Weak force

Vocabulary for quiz on Monday

• element
• pure substance
• metal
• metaloid
• nonmetal
• compound
• mixture
• conductor
• thermal and electrical conductivity
• malleable
• ductile
• brittle
• law of definite proportions (pg 86)
• chemical properties
• physical properties
• chemical change
• physical change

this unit assumes a mastery of vocab from previous unit on physical characteristics: density, solubility, conductivity, etc.