Chapter 2 Flashcards
(44 cards)
List Dalton’s 4 postulates?
1) all matter = made up of indivisible/indestructible atoms | 2) all atoms in an element have the same mass/properties | 3) compounds = 2+ different atoms | 4) chemical reaction = rearrangement of atoms
What was JJ Thompson’s model of the atom? Who disproved this model?
positively charged sphere has electrons embedded within the sphere | Ernest Rutherford
What was Ernest Rutheford’s model of the atom?
positive charge = resides in the nucleus | empty surrounding space = electrons floating
What is the role of the neutron in the nucleus?
adds mass and prevents protons from repelling each other in the nucleus
What is the composition of the atom?
electrons and protons = equal amount | neutrons and protons = in the nucleus
Protons: size, charge, mass
large | +1 | 1.0073 amu
Electrons: size, charge, mass
very small | -1 | 5.486e-4 amu
Neutron: size, charge, mass
large | 0 | 1.0087 amu
What are the 3 subatomic particles?
protons, neutrons, electrons
***Atom: size, charge, mass
1-5 A |
What is the atomic number of an element? What is carbon’s atomic number?
number of protons in an element | carbon = 6
Which changes in number when it comes to isotopes: protons or neutrons? What is carbon-14?
neutrons | carbon-14 = 2 extra neutrons (total of 8 neutrons)
What are isotopes?
atoms with same atomic numbers but different mass numbers
What is atomic weight?
the average atomic mass of an element that has isotopes
What are the properties of an electron as seen in cathode rays?
negatively charged particles were found to flow from cathode tubes = fluroescence
What was Millikan’s oil-drop experiment?
small drops of oil fell between 2 electrically charged plates = measured the varying voltages between the plates affected the fall
What did Millikan’s oil-drop experiment measure about the electron?
it determined the charge of the electron = negative
What is the experimental evidence for the nuclear nature of the atom?
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What are groups of the periodic table?
vertical columns
What are the periods of the periodic table?
horizontal rows
What is group 1A of the periodic table?
alkali metals
What is group 2A of the periodic table?
alkaline earth metals
What is group 6A of the periodic table?
chalcogens
What is group 7A of the periodic table?
halogens
