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atom - ANS Basic unit of matter; made of protons, neutrons, and electrons; have a
nucleus that contains p and n and an electron cloud that surrounds it
proton - ANS A subatomic particle that has a positive charge and that is found in the
nucleus of an atom
neutron - ANS A subatomic particle that has no charge and that is found in the nucleus
of an atom
electron - ANS A subatomic particle that has a negative charge and is found outside of
the nucleus
masses of subatomic particles - ANS the proton and neutron have almost the same
mass, and the electron is 2000 x lighter; protons and neutrons are each about 1 amu
electron cloud - ANS a region around the nucleus of an atom where electrons are likely
to be found; used because it is hard to tell exactly where electrons are at a given
moment
atomic number - ANS the number of protons in the nucleus of an atom; represented by
the letter Z; written in the subscript in from of the atomic symbol; all atoms of the same
element have this same value; this number does not change, therefore it determines the
type of atom
mass number - ANS the total number of protons and neutrons in the nucleus of an
atom; represented by the letter A; written in the superscript in from of a chemical
symbol; this number can differ due to isotopes (when the # of neutrons is different)
isotopes - ANS Atoms of the same element that have different numbers of neutrons; all
atoms have them; all isotopes of an element have similar chemical properties
, ion - ANS A charged atom
cation - ANS A positively charged ion that loses an electron
anion - ANS A negatively charged ion that gains an electron
neutral atoms - ANS have the same number of protons and electrons
subatomic particles - ANS protons, neutrons, electrons
nucleus - ANS Center of an atom that contains protons and neutrons
Rutherford's discoveries - ANS discovered that protons are much larger than electrons
and they are concentrated in the center of the atom, or the nucleus; did the atom
scattering experiment with the alpha particles and the gold foil to demonstrate that the
positive charges of an atom are concentrated in the center and not evenly distributed
(which the plum pudding model described); a small # of alpha particles were
significantly deflected (they hit right on the small nucleus)
volume and mass of an atom - ANS the electron cloud takes up most of the volume, but
the nucleus takes up most of the mass
atomic mass unit (amu) - ANS 1/12 the mass of one carbon-12 atom; 1.6605 x 10^-24
g
Dalton (Da) and Unified Atomic Mass Unit (u) - ANS alternative unit equivalent to the
atomic mass unit
fundamental unit of charge - ANS also known as the elementary charge; the magnitude
of the charge of an electron; e= -1.602 x 10^-19 c (coulomb)
masses of subatomic partibles - ANS p = 1.0073 amu
n = 1.0087 amu
e = 0.00055 amu
A person's mass is 100 kg. What is their mass in amu? - ANS 6.022 x 10^28 amu
how to solve for the number of neutrons in an atom - ANS mass number (A) - atomic
number (Z)