CH2: THE CHEMICAL CONTEXT OF LIFE Flashcards
anything that takes up space and has mass; made up of elements
Matter
a substance that cannot be broken down to other substances by chemical reactions
Element
a substance consisting of two or more different elements combined in a fixed ratio; has characteristics different from those of its elements (emergent properties)
Compound
elements an organism needs to live a healthy life and reproduce (20-25% of 92 elements)
Essential Elements
required by an organism in only minute quantities.
Trace Elements
substances that if you interact with it in a certain way can kill or harm
Toxins
a toxin you ingest
Poison
when another organism intentionally bites you
Venom
the smallest unit of matter than still retains the properties of an element; made of subatomic particles
Atom
make up atoms
Subatomic Particles
Name the 3 Subatomic Particles
Neutrons
Protons (large)
Electrons (small)
center of an atom where protons and neutrons are packed together tightly
Atomic Nucleus
Where are the electrons in relation to the atomic nucleus
electrons form an electron cloud (caused by rapid movement) around the nucleus
the unit of measure for atoms and subatomic particles
Daltons
the number of protons in the nuclei of an element (left subscript)
Atomic Number
protons + neutrons in the nucleus of an atom (left superscript)
Mass Number
the approximation of the total mass of an atom
Atomic Mass
the different atomic forms of the same element (different number of neutrons, so different weights); different masses but chemically identical
Isotopes
isotopes that their nuclei do not have a tendency to lose subatomic particles
Stable Isotopes
one in which the nucleus decays spontaneously, giving off particles and energy
Radioactive Isotope
can track atoms through metabolism
Radioactive Tracers
the time it takes for 50% of the parent isotope to decay into its daughter isotope at a fixed rate
Half-Life
scientists measure the ratio of different isotopes and calculate how many half-lives have passed since the fossil or rock was formed
Radiometric Dating
the capacity to cause change (i.e. doing work)
Energy
the energy that matter possess because of its location or structure
Potential Energy
where electrons are found, each ______ has a characteristic average distance and energy level
Electron Shell
Electrons CLOSE to nucleus = ______ potential energy
less
Electrons FARTHER from nucleus = ______ potential energy
more
outermost electron shell
Valence Shell
Outermost electrons
Valence Electrons
chemically unreactive (atoms with completed valence shells)
inert
Elements react based on their _________
electrons (in their valence shell)
three-dimensional space where an electron is found 90% of the time (1s, 2s, 2p, 3s…); not really cloud, more of a specific shape
Orbital
the attractions that hold atoms close together when they interact
Chemical Bonds
the SHARING of a pair of valence electrons by two atoms
Covalent Bond
are made up of two or more atoms held together by covalent bonds
Molecule
represents molecules (i.e. H2)
Molecular Formula
H:H
Lewis Dot Structure
H–H
Structural Formula
the attraction of a particular atom for the elctrons of a covalent bond (more _________ = partial negative)
Electronegativity
electrons are shared equally in covalent bonds because the two atoms have the same electronegativity
Nonpolar Covalent
an atom is bonded to a more electronegative atom, the electrons of the bond are not shared equally (partial negatives and partial positives)
Polar Covalent
bond formed by the attraction of a cation and anion; one donates/transfers electron to another
give away electron = more positive (cation)
gains electron = more negative (anion)
Ionic Bond
charged atoms or molecules
Ions
compounds formed by ionic bonds (found in crystals)
Ionic Compounds or Salts
attraction between a hydrogen and an electronegative atom
Hydrogen Bonds
when atoms and molecules are very close together because electrons may not be evenly distributed
Van der Waals Interactions
the making and breaking of chemical bonds, leading to changes in the composition of matter; reversible
Chemical Reactions
the point at which the reactions offset one another exactly; rxn still happening but with no net effect on the concentrations of reactants and products (stabilized concentrations at a particular ratio)
Chemical Equilibrium
father of the periodic table
Dmitri Ivanovich Mendeleev
proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus
Neils Bohr
