chapter 2 pt1

Anything that has mass and occupies space

• Solid—definite shape and volume
• Liquid—definite volume, changeable shape
• Gas—changeable shape and volume

to do work or put matter into motion

• Kinetic—energy in action
• Potential—inactive energy

• Chemical energy—stored in bonds of chemical substances
• Electrical energy—results from movement of charged particles
• Mechanical energy—directly involved in moving matter
• Radiant or electromagnetic energy—exhibits wavelike properties (i.e., visible light, ultraviolet light, and X-rays)

• Energy may be converted from one form to another
• Conversion is inefficient because some energy is “lost” as heat

• Cannot be broken down by ordinary chemical means
• Each has unique properties:
• Physical properties
• Are detectable with our senses, or are measurable
• Chemical properties
• How atoms interact (bond) with one another

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

• About 3.9% of body mass:
• Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesiumAtomic Structure (Mg), iodine (I), and iron (Fe)

• Unique building blocks for each element
• Atomic symbol: one- or two-letter chemical shorthand for each element

• Determined by numbers of subatomic particles
• Nucleus consists of neutrons and protons

• No charge
• Mass = 1 atomic mass unit (amu)

• Positive charge
• Mass = 1 amu

• Orbit nucleus
• Equal in number to protons in atom
• Negative charge Planetary model—oversimplified, outdated model
• Incorrectly depicts fixed circular electron paths
• Useful for illustrations (as in the text)
• 1/2000 the mass of a proton (0 amu)

• Depicts probable regions of greatest electron density (an electron cloud)
• Useful for predicting chemical behavior of atoms

all chemical reactions that occur in body cells….

chemical reactions that breakdown large food molecules into small chemical units in order to release energy

chemical reactions that join simple molecules to form biomolecules