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Components of the Atom Nucleus: Nuclear Forces:

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Presentation on theme: "Components of the Atom Nucleus: Nuclear Forces:"— Presentation transcript:

1 Components of the Atom Nucleus: Nuclear Forces:
Small densely packed area located at the center of the atom Nuclear Forces: Forces that allow protons and neutrons to exist close together in the nucleus Electron Cloud (orbitals) The large volume area that surrounds the nucleus Subatomic particles Particles that make up the atom Quantity of these parts determine an element’s chemical/physical properties

2 Subatomic Particles Particle Charge Symbol Location Grams AMU* Proton
Positive p+ Nucleus 1.673e-24 1 Neutron Neutral n0 1.675e-24 Electron Negative e- Cloud 9.11e-28 * AMU = atomic mass unit

3 Characteristics of Atoms
All matter is composed of atoms Atoms of one element differ in properties from atoms of another element Atoms are neutral (p+ = e-) Atoms are mostly made of empty space.

4 Element Symbols 12 Mass Number C 6 Atomic Number C-12 Mass Number

5 Examples: Atomic number Mass number p+ e- n0 O 30 238 146 8 8 16 8 8 Zn 65 30 30 35 U 92 92 92

6 Difference between an Atom, Ion, and Isotope
Charged particles (positive or negative) # of electrons change (p+ ≠ e-) Isotope: # of neutrons change Masses are different since the # of neutrons are different ** If the # of protons change, the element changes **

7 Isotopes Where to find the mass number of isotopes:
Information will be given either 3 ways Name: carbon-14 or C-14 Symbol: 14C Adding given # no to p+ (or atomic #) The Atomic Mass of an Isotope will be given. It can not be taken from the periodic table.

8 Atomic Masses The weighted average of all the isotopes masses known for an element Masses found on periodic table are atomic masses All elements have isotopes: some are radioactive What you are given when trying to calculate atomic mass Each known isotope and it’s atomic mass The percent abundance (how often it occurs) for each element

9 Atomic Masses The atomic mass is 27.9 amu
Calculate the atomic mass of Si based on the following isotopes of Silicon: Si-28 Mass: % Si-29 Mass: % Si-22 Mass: % 1) Multiple the mass of each isotope by the abundance Note: the percent must be in decimal form 2) Add the products above to find the atomic mass The atomic mass is 27.9 amu

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