Chapter 2 vocabulary Flashcards
(50 cards)
The study of the molecules that compose living organisms
biochemistry
the simplest form of matter to have unique chemical properties
element
number of protons in the nucleus
atomic number
inorganic elements that are extracted from the soil by plants and passed up the food chain to humans and other organisms
minerals
Electrons in the outermost shell
valence electrons
varieties of an element that differ from one another only in number of neutrons and therefore in atomic mass
isotopes
unstable isotopes
radioisotopes
Process of decay
radioactivity
the time required for 50% of its atoms to decay to a more stable state
physical half-life
the time required for half of a radioisotope to disappear from the body
biological half-life
charged particles with unequal numbers of protons and electrons
ions
the particle that gains electrons acquires a negative charge
anion
loses electrons, acquires a positive charge
cation
substances that ionize in water and form solutions capable of conducting electricity
electrolytes
chemical particles with an odd number of electrons
free radicals
a chemical that neutralizes free radicals
antioxidant
chemical particles composed of two or more atoms united by a chemical bond
molecules
molecules composed of two or more elements
compounds
molecules with identical molecular formulae but different arrangements of their atoms
isomers
the sum of the atomic weights of atoms
molecular weights
a molecule is held together, and molecules are attracted to one another, by forces called
chemical bonds
the attraction of a cation to an anion
ionic bond
bond formed by the sharing of electrons
covalent bonds
a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another
hydrogen bond
