Chapter 1

• An electron is the smallest amount of electric charge having the characteristic called negative polarity.
• The proton is a basic particle with positive polarity.
• A neutron has no electrical charge, but it does have mass.
• Electrons are negatively charged particles that orbit around the nucleus of an atom.
• Protons are positively charged particles located at the center of an atom's nucleus.
• Neutrons are neutral (uncharged) particles found within the nucleus of an atom.
• Atoms can be represented by their atomic number (number of protons) or their mass number (sum of protons and neutrons).
• Isotopes are different forms of elements with the same number of protons but varying numbers of neutrons.
• The atomic number represents the number of protons in an atom.
• Isotopes are atoms of the same element with different numbers of neutrons.
• An ion is an electrically charged atom formed when electrons are added to or removed from its outer shell.
• Ions can be either cations (positively charged) or anions (negatively charged).
• The periodic table is organized based on increasing atomic number, which determines the element's properties.
• Elements to the left of the periodic table tend to lose electrons easily, while those to the right gain them readily.
• A compound is formed when two or more elements chemically combine.
• Electric charge


  Basic particles with opposite polarities
• Basic particles of electric charge

  • Electron
  • Proton
• Electron


  Smallest amount of electric charge with negative polarity
• Proton


  Basic particle with positive polarity
• Negative and positive polarities indicate two opposite characteristics that seem to be fundamental in all physical applications
• Just as magnets have north and south poles

  Electric charges have opposite polarities labeled negative and positive
• The opposing characteristics provide a method of balancing one against the other to explain different physical effects
• The arrangement of electrons and protons as basic particles of electricity determines the electrical characteristics of all substances
• The neutral condition means that opposing forces are exactly balanced, without any net effect either way
• Using the electrical forces associated with the negative and positive charges in all matter


  1. Work must be done to separate the electrons and protons

  2. Changing the balance of forces produces evidence of electricity
• Although there are any number of possible methods by which electrons and protons might be grouped, they assemble in specific atomic combinations for a stable arrangement
• Atom


  The smallest particle of the basic elements which forms the physical substances we know as solids, liquids, and gases
• The proton in the nucleus makes it the massive and stable part of the atom because a proton is 1840 times heavier than an electron
• Free electrons


  Electrons that can move freely from one atom to the next
• The movement of free electrons provides electric current in a metal conductor
• Without any applied voltage

  The net effect in the wire is zero because of the random motion of the free electrons
• When voltage is applied

  It forces all the free electrons to move in the same direction to produce electron flow, which is an electric current
• An element is defined as a substance made up of atoms having the same number of protons, regardless of how many neutrons they have.
• A cation has lost one or more electrons, resulting in a positive charge.
• An anion gains one or more electrons, resulting in a negative charge.
• Conductor


  A material in which electrons can move easily from atom to atom
• Conductors


  • Metals
  • Silver (best)
  • Copper (second best)
• Metals as conductors


  • Their atomic structure allows free movement of the outermost orbital electrons
• Copper wire is generally used for practical conductors because it costs much less than silver
• Purpose of using conductors


  To allow electric current to flow with minimum opposition