Ch.2- Basic Chemistry

• Matter


  -Anything that has mass and takes up space(weight)

  - Solids, Liquids, and Gasses

  - Physical & Chemical changes
• Energy


  the ability to do work
• Kinetic energy


  when energy is actually doing work
• Potential Energy (PE)


  When energy is inactive or stored
• Forms of Energy


  chemical, electrical, mechanical, radiant
• Chemical energy


  stored in bonds of chemical substances
• Electrical energy


  results from the movement of charged particles-ions
• Mechanical energy


  directly involved in moving matter- muscles
• Radiant energy


  travels in waves- the electromagnetic spectrum including x-rays, infrared, light, radio, and UV rays
• Fundamental units of matter


  can't be broken down into smaller units
• 96% of the body is made from 4 elements

  Carbon (C), Oxygen (O), Hydrogen (H), Nitrogen (N)
• Atoms


  building blocks of elements
• Inside the nucleus


  protons and neutrons
• Outside the nucleus


  electrons
• Atomic number


  equal to the number of protons that the atoms contain - also equals the number of electrons
• Atomic Mass Number (amu)


  Sum of protons and neutrons
• Isotopes


  -Have the same number of protons and electrons, but the same atomic number

  - Vary in number of neutrons so different atomic masses
• Atomic weight


  -close to mass number of most abundant isotope

  -atomic weight reflects natural isotope variation
• Radioisotopes


  -Heavy isotope

  - Tends to be unstable

  - Decomposes to move stable isotope
• Radioactivity


  - process of spontaneous atomic decay

  - releases particles (alpha, beta, and gamma rays)
• Molecule


  2 or more atoms combined chemically
• Compound


  2 or more DIFFERENT atoms combined chemically
• Chemical Reactions


  Occurs when atoms combine or dissociate from other atoms
• In chemical reactions, atoms are

  -united by chemical bonds

  -dissociated from other atoms when chemical bonds are broken
• Electrons


  -Negatively charged particles

  - occupy energy levels called electron levels or shells

  - closest to the nucleus and most strongly attracted
• Each shell has distinct properties


  -The number of electrons has an upper limit

  -Shells closest to the nucleus fill first
• Bonding


  Involves interactions between electrons in the outer shell(Valence shell)
• Full valence shells do not form


  bonds
• Inert elements


  have complete valence shells and are stable
• Rules of 8s

  Step 1: Shell 1 has 2

  Step 2: Shell 2 has 10 electrons

  Step 3: Shell 3 has 18 electrons
• Reactive Elements


  -valence shells are not full and are unstable

  -tend to gain, lose, or share electrons

  -allows for bond formation, which produces stable valence
• Ionic bonds


  form when electrons are completely transferred from one atom to another
• Ions


  -charged particles

  - either donate or accept electrons
• Anions


  negatively charged ions (accept electrons)
• Cations


  positively charged ions (donate electrons)
• Opposites attract so stick together


  most form salts
• Covalent Bonds


  -atoms become stable through shared electrons

  - Single covalent bonds share one electron

  - Double covalent bonds share two electrons
• Covalent bonded molecules

  -some are non-polar: electrically neutral as a molecule

  -some are polar: have a positive and negative side
• Polar molecules orient themselves toward other

  polar or charged particles
• Hydrogen bonds


  -weak chemical bonds

  -hydrogen is attracted to the negative portion of polar molecule

  -provides attraction between molecules