Chapter 2: The Chemical Context of Life Flashcards
Negatively charged ion
Anion
Smallest unit of life
Atom
Total mass of an atom, accounting for their isotopes
Atomic Mass
The number of protons in the nucleus of an atom, unique for each element and designated by a subscript
Atomic Number
An atoms dense central core, containing protons and neutrons
Atomic Nucleus
Positively charged ion
Cation
Attraction between 2 atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. Bonded atoms gain a complete outer valence shell with full
8 electrons.
Chemical Bond
In chemical reaction, the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of reactants and products do not change with time
Chemical Equilibrium
Making and breaking of chemical bonds, leading to charges in the composition of matter
Chemical Reaction
Substance consisting of two or more different elements combined in a fixed ratio
Compound
Strong chemical bond in which 2 atoms share one or more pairs of valence electrons
Covalent Bond
Double covalent bond; the sharing of two pairs of valence electrons by two atoms
Double Bond
Type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity
Electron
Attraction of a given atom for the electrons of a covalent bond
Electronegativity
An energy level of electrons at a characteristic average distance from the nucleus of an atom
Electron Shell
Any substance that can not be broken down to any other substance by chemical reactions
Element
The capacity to cause change, especially to do work
Energy
Chemical element required for an organism to survive, grow, and reproduce
Essential Element
Weak chemical bond that is formed when the slightly positive hydrogen atom if a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule
Hydrogen Bond
An atom or group of atoms that has gained or lost one or more electrons; thus acquiring a charge
Ion
A chemical bond resulting from the attraction between opposite charged ions (anions/cations)
Ionic Bond
Compound resulting from the formation of an ionic bond; also called salts
Ionic Compound
One of several atomic forms of an element, each with the same number of protons but different number of neutrons. Changing its atomic mass
Isotope
Total number of protons and neutrons in an atom’s nucleus
Mass Number
Anything that takes up space and has mass
Matter
Two or more atoms held together by covalent bonds
Molecule
Type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity
Nonpolar Covalent Bond
Subatomic particle having no electrical charge
Neutron
3D space where an electron is found 90% of the time
Orbital
Covalent bond between atoms that differs in electronegativity. The electrons are pulled closer to the more electronegative atom, making it slightly more negative and the other more positive
Polar Covalent Bond
Potential Energy
A material resulting from the chemical reaction
Product
Subatomic particle with single positive electrical charge
Proton
An isotope that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy
Radioactive Isotope
Starting materials in the chemical reaction
Reactant
Compound resulting from the formation of an ionic bond; also called an ionic compound
Salt
Single covalent bond; the sharing of a pair of valence electrons by two atoms
Single Bond
An element indispensable for life but required in extremely minute amounts
Trace Element
Bonding capacity of a given atom, the number of covalent bonds an atom can form, which usually equals the number of electrons in its outermost shell
Valence
An electron in the outermost electron shell
Valence Electron
The outermost energy shell of an atom, containing the electrons involved in the chemical reactions of that atom
Valence Shell
Weak attractions between molecules or parts of molecules that result from transient local partial charges
Van Der Waals Interactions
