Chapter 2 Flashcards
Pure Substance, composed of atoms, basic raw material of everything
element
What elements mostly make up organisms?
Oxygen, Carbon, Nitrogen, and Hydrogen
smallest unit that has properties of a given element, made up of subatomic particles
Atom
Is in the center of an atom, is the atomic number of the atom
proton
has no charge, is in the center of an atom
neutron
located in energy shells around the nucleus of an atom
electron
Mass Number - Atomic Number
Gives you the number of neutrons in an atom
Varying form of an atom, different number of neutrons
Isotope
simplest atom, consists of a single electron in one shell
Hydrogen
Shells around a nucleus equivalent to energy levels
Orbital
outermost orbital, basis for chemical bonds that form molecules
valance shell
When is an atom most stable? What can provide stability?
When its outermost shell is filled. Chemical Bonds
Atoms with no vacancies in outer shell, usually do not take part in chemical reactions
Inert atoms
Combination of two or more elements. Require chemical bonds. Proportions never vary
Compound
Two or more kinds of molecules ‘mingle’. does not require formation of a bond. proportions may be different
Mixture
joins atoms with opposite electrical charges
Ionic Bond
atoms share electrons. strong and stable.
Covalent bond
two atoms pull equally on electrons. no charge at the two ends
Nonpolar Covalent bonds
do not pull equally on electrons. One with most protons pulls more
polar covalent bond
weak link formed between a covalently bonded ______ atom and another atom taking part in a separate covalent bond
Hydrogen Bond
Water is what type of covalent bond? Polar molecules are attracted to what?
Polar, water
Water helps to stabilize what in cells? What produces heat inside cells?
temperature, chemical reactions
What causes heat loss?
Evaporation
Ions and polar molecules dissolve easily in it, what is the solvent?
Water
This substance is dissolved in a solvent, what is it?
solute
These constantly add and remove substances from body fluids. The body must manage these changes.
Chemical reactions
measures the relative concentration of H+ in fluids
pH scale
donates protons/hydrogen ion (as H+)
Acid
accepts H+
Base
Compounds that release ions other than H+ and OH- in solutions
Salts