Chapter 2 chemical level of organization Flashcards
Principle elements of human body
O2-oxygen, C-carbon, H-hydrogen, N-nitrogen. Secondary: Ca2+-calcium, Ch-chlorine, K-potassium, S-sulfur, P-phosphorus, Na+ sodium, Mg-magnesium, Fe-iron.
atom
the smallest units of matter that retain the properties and characteristics of the element.
nucleus, proton, neutron, electron
. The dense central core of an atom is its nucleus. Within the nucleus are positively charged protons (p+) and uncharged (neutral) neutrons (n). The tiny, negatively charged electrons (e-) move about in a large space surrounding the nucleus.
electron shell (valence shell)
simple circles around the nu- cleus. Because each electron shell can hold a specific number of electrons, the electron shell model best conveys this aspect of atomic structure
atomic number
number of protons
atomic mass
number of protons +neutrons
isotopes
are atoms of an element that have different numbers of neutrons and therefore different mass numbers.
atomic mass
Dalton/atomic mass unit- average mass of its common occurring isotope
Ion
is an atom that has a positive or negative charge because it has unequal numbers of protons and electrons
Ionization
is the process of giving up or gaining electrons.
molecule
2 atoms of same kind
compound
2 or more atoms of different elements
free radical
atom or group of atoms with unpaired electron in outermost shell- unstable, reactive and desctructive
Octet rule
valence shell can only hold 8, stable, barely binds
ionic bond
cation +, anion- bind by neg and pos charge, cation donates electron to anion.
electrolyte
ionic compound that breaks apart into + & - ions in solution
covalent
share electron
single covalent bond, double covalent bond, triple covalent bond
2 atoms share one electron pair, share 2 pairs, share 3 pairs
non-polar covalent bond
two atoms share the electrons equally—one atom does not attract the shared electrons more strongly than the other atom.
electronegativity
power to attract electrons to itself. (greater pull=greater electronegativity)
hydrogen bond
(weakest bonds), hydrogen bond forms when a hydrogen atom with a partial positive charge attracts the partial negative charge of neighboring electronegative atoms, most often larger oxygen or nitrogen atoms. hydrogen bonds result from attraction of oppositely charged parts of molecules