A&P 2: Chemistry Comes Alive Flashcards
Matter
anything that occupies space and has mass
Energy
capacity to do work, or to put matter in motion
Kinetic energy
energy in action
Potential energy
stored energy; inactive energy that has the capability to do work but is not presently doing so
Chemical energy
form of energy stored in the bonds of chemical substances
Electrical energy
results from the movement of charged particles
Mechanical energy
energy directly involved in moving matter
Radiant energy (electromagnetic energy)
energy that travels in waves
Elements
all matter is composed of these unique substances that cannot be broken down into simpler substances by ordinary chemical methods
Periodic table
provides a more complete listing of the known elements and helps to explain the properties of each element that makes it react as it does with other elements
Atoms
each element is composed of more or less identical particles (building blocks)
Physical properties
those we can detect with our senses, e.g. color, texture
Chemical properties
pertain to the way atoms interact with other atoms (bonding behavior) and account for the facts that iron rusts, animals can digest their food, etc.
Atomic symbol
each element is designated by a 1 or 2 letter chemical shorthand, usually the 1st letter of the element’s name
Nucleus
atom has a central one of these containing protons and neutrons tightly bound together
Protons
bear a positive charge
Neutrons
neutral part of the nucleus
atomic mass unit (amu)
protons and neutrons are heavy particles and have approximately the same mass, 1 of these
Electrons
bear a negative charge equal in strength to the positive charge of the proton
Planetary model
simplified, outdated model of atomic structure
Orbitals
regions around the nucleus in which a given electron or electron pair is likely to be found most of the time
Orbital model
modern model of atomic structure; depicts probable regions of greatest electron density by denser shading (electron cloud)
Atomic number
equal to the number of protons in its nucleus and is written as a subscript to the left of its atomic symbol
Mass number
sum of the masses of its protons and neutrons
Isotopes
nearly all known elements have two or more of these structural variations, which have the same number of protons (and electrons) but differ in the number of neutrons
Atomic weight
average of the relative weights (mass numbers) of all the isotopes of an element, taking into account their relative abundance in nature; approximately equal to the mass number of its most abundant isotope
Radioisotopes
isotopes that exhibit radioactivity
Molecule
combination of 2 or more atoms held together by chemical bonds
Compound
when 2 or more different kinds of atoms bind
Mixtures
substances composed of 2 or more components physically intermixed
Solutions
homogeneous mixtures of components that may be gases, liquids, or solids
Solvent
substance present in the greatest amount in a solution; usually liquids
Solutes
substances present in smaller amounts in a solution
Percent
parts per 100 parts
Molarity (M)
moles per liter
Mole
a ____ of any element or compound is equal to its atomic weight or sum of the atomic weights
Molecular weight
sum of atomic weights in grams
Avogadro’s number
6.02 x 10^23; number of particles in one mole of a substance
Colloids
emulsions; heterogeneous mixtures; composition is dissimilar in different areas of the mixture; often appear translucent/milky; scatter light but do not settle
Sol-gel transformations
ability to change reversibly from a fluid state to a more solid state
Suspensions
heterogeneous mixtures with large, often visible solutes that tend to settle out
Chemical bonds
when atoms combine with other atoms, they are held together by these
Electron shells
electrons forming the electron cloud around the nucleus of an atom occupy these regions of space that consecutively surround the atomic nucleus
Energy level
each electron shell represents a different one of these
Valence shell
indicates an atom’s outermost energy level or that portion of it containing the electrons that are chemically reactive
Octet rule (rule of 8’s)
except for shell 1 which is full when it has 2 electrons, atoms tend to interact in such a way that they have 8 electrons in their valence shell
Ions
charged particles that form due to the transfer of electrons
Ionic bond
chemical bond between atoms formed by the transfer of 1 or more electrons from 1 atom to another
Anion
gains 1 or more electrons; electron acceptor; acquires a net negative charge
Cation
atom that loses electrons; electron donor; acquires a net positive charge
Crystals
large arrays of cations and anions held together by ionic bonds
Covalent bonds
electron sharing produces molecules in which the shared electrons occupy a single orbital common to both atoms, which constitutes this type of bond
Nonpolar molecules
equal sharing of electrons (do not have separate + and - poles of charge)
Polar molecule
unequal electron pair sharing, especially in non-symmetrical molecules containing atoms with different electron-attracting abilities
Electronegativity
electron-hungry; capability to attract electrons very strongly
Electropositive
electron-attracting ability is so low that an atom usually loses its valence shell electrons to other atoms; potassium and sodium are good examples