a&p 1 chemistry

Matter

Anything that has mass and occupies space

States of matter:

Solid�definite shape and volumeLiquid�definite volume, changeable shapeGas�changeable shape and volume

Energy

Capacity to do work or put matter into motionTypes of energy:Kinetic�energy in actionPotential�stored (inactive) energy

Forms of Energy

Chemical energy�stored in bonds of chemical substances Electrical energy�results from movement of charged particlesMechanical energy�directly involved in moving matterRadiant or electromagnetic energy�exhibits wavelike properties (i.e., visible light, ultraviolet light, and X-rays)

Energy Form Conversions

Energy may be converted from one form to anotherConversion is inefficient because some energy is �lost� as heat

Composition of Matter

ElementsCannot be broken down by ordinary chemical means Each has unique properties:Physical propertiesAre detectable with our senses, or are measurableChemical propertiesHow atoms interact (bond) with one another

Composition of Matter

AtomsUnique building blocks for each elementAtomic symbol: one- or two-letter chemical shorthand for each element

Major Elements of the Human Body

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

Lesser Elements of the Human Body

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

Trace Elements of the Human Body

< 0.01% of body mass: Part of enzymes, e.g., chromium (Cr), manganese (Mn), and zinc (Zn) Atomic Structure Determined by numbers of subatomic particles Nucleus consists of neutrons and protons

Atomic Structure

NeutronsNo chargeMass = 1 atomic mass unit (amu)ProtonsPositive chargeMass = 1 amu

Atomic Structure

ElectronsOrbit nucleusEqual in number to protons in atomNegative charge 1/2000 the mass of a proton (0 amu)

Models of the Atom

Orbital model: current model used by chemistsDepicts probable regions of greatest electron density (an electron cloud)Useful for predicting chemical behavior of atoms

Models of the Atom

Planetary model�oversimplified, outdated modelIncorrectly depicts fixed circular electron pathsUseful for illustrations (as in the text)

Atomic Structure

Determined by numbers of subatomic particlesNucleus consists of neutrons and protons