Unit 7 – atomic structure – Flashcards
Unlock all answers in this set
Unlock answersquestion
democritus
answer
"atoms are tiny, indivisible, and indestructible" not based on scientific method
question
Dalton's atomic theory
answer
1. all elements are made of tiny indivisible particles called atoms 2. atoms of same element are identical. atoms of one element are different from those of another element 3. atoms of different elements can physically mix together or can chemically combine in simple whole-number rations to form compounds 4. chemical reactions occur when atoms are separated, joined, or rearranged. atoms of one element are never changed into atoms of another element
question
atom
answer
smallest particle of an element that retains that element's properties
question
scanning tunneling microscopes
answer
observe individual atoms nanotechnology
question
thomson
answer
discovered negatively charged subatomic particles (electron) using a cathode ray, determined charge to mass ratio for electrons
question
cathode ray tube experiment
answer
magnet deflects cathode ray, charged metal plates deflect cathode ray, (+) plate attracts, (-) plate repels, the ray is a stream of negative particles (election), didn't matter what type of gas or metal was used in the electrodes so electrons must be in all atoms
question
Milikan
answer
determined charge of an electron (-1), used charge and charge to mass ratio from Thomson to calculate the mass of an electron
question
thomson's plum pudding model
answer
the atom is a uniform, positively charged sphere, with electrons stuck in it; like a chocolate chip cookie: dough is positively charged sphere and chips are electrons
question
Rutherford's gold foil experiment
answer
tested plum-pudding model: shot heavy, positively charged particles at thin sheet of gold and expected the particles to be very slightly deflected; most alpha particles went straight through (no deflection), some bounced straight back
question
Rutherford
answer
discovered atoms are mostly empty space, all the positive charge and mass of the atom are in the nucleus, established the nuclear atom
question
Eugene Goldstein
answer
observed a positively charged particle (protons: positively charged, about 2,000 x more mass than an electron) in cathode ray tubes
question
James Chadwick
answer
discovered the neutrons: no charge, but mass equal to proton's mass
question
e-
answer
symbol of electron
question
p
answer
symbol of proton
question
n
answer
symbol of neutron
question
1-
answer
charge of electron
question
1+
answer
charge of proton
question
1/1840
answer
relative mass of electron
question
1+
answer
relative mass of proton
question
bohr model of the atom
answer
an electron moves around the nucleus only in certain allowed circular orbits
question
atomic number
answer
number of protons, identifies the element, # protons = # electron in a neutral atom
question
isotopes
answer
atoms with the same number of protons but different number of neutrons
question
mass number
answer
protons + neutrons
question
average atomic mass
answer
weighted atomic mass of all the isotopes of that element it reflects mass and relative abundance of the isotopes as they occur naturally
