Atoms, Ions, and Isotopes
How many neutrons are in Phosphorus-31?
16 neutrons
Write the balanced nuclear reaction for when Manganese – 56 emits a beta particle
5625Mn -> 0-1e +5626Fe
What Separation technique would you use to separate the following:
Salt Water
evaporation
Who did the cathode ray tube experiment and found that an electron has a negative charge? Incorrectly proposed the “Plum Pudding'' model of an atom.
J.J Thomson
How many significant digits are in the following measurement?
0.070 mm
2 Sig figs
Isotopes are atoms of the same element with a different _________ _______.
mass number
What happens to the mass number and the atomic number of Uranium – 235 when it undergoes alpha decay?
mass decreases by four
atomic number decreases by 2
23190Th
Which of the following is a Heterogeneous mixture.
Carbon
Water
Salt water where all of the salt is dissolved
Pasta and water
Air
Brass
Iron
4. Pasta and Water
Who did the gold foil experiment and found that an atom is just empty space with a small dense, positive center?
Ernst Rutherford
How many grams of Nickel should a student measure if they need 5.78 moles of nickel?
339 g pf Nickle
what is the name of the isotope with 33 protons, 33 electrons, and a mass number of 76.
Arsenic-76
A radioactive isotopes decays from 70.500 grams to 8.8125 grams in the span of 18.5 hours. What is the half – life of this isotope?
6.17 hours
Which of the following represent a physical property or change?
Density
flammability
smell
melting
reacts with oxygen
digesting food
Density
smell
melting
Who did the oil drop experiment and was able to calculate the actual charge of an electron…and determined the very very very small mass of an electron?
Robert Millikan
How many moles of strontium are in a sample that contains 7.80 ×1022 atoms?
0.130 moles of strontium
3717Cl-1
The half – life of Mercury – 202 is 60 seconds. How much remains of a 50.0 gram sample after 4 minutes?
3.125 g
Which of the following represent a homogeneous mixture?
Carbon
Water
Salt water where all of the salt is dissolved
Pasta and water
Air
Brass
Iron
Salt water where all of the salt is dissolved
Air
Brass
True or False: Greek philosopher Democritus believed....
Matter is composed of empty space through which atoms move.
Atoms are solid, homogeneous, indestructible and indivisible.
Different kinds of atoms have different sizes and shapes.
Changes in matter result from changes in the combination of atoms and not from changes in the atoms themselves.
True
The percent abundance of Sulfur – 32 is 90.5% abundant. The other isotope of sulfur is Sulfur – 33. What is the average atomic mass based on these figures?
32.095 amu
which of the following is a cation?
a. Potassium with 19 electrons
b. Arsenic with 33 electrons
c. Chlorine with 18 electrons
d. Sodium with 10 electrons
e. Sulfur with 18 electrons
d. Sodium with 10 electrons
Cation has a positive charge
what happens to the mass number and atomic number of Uranium-235 when it undergoes beta decay?
Mass stays the same
Atomic number increases by one
List the 6 phase changes and indicate whether they are endothermic or exothermic processes.
Vaporization- Endo
Condensation- Exo
Melting- Endo
Freezing- Exo
Deposition- Exo
Sublimation- Endo
True or False: Dalton's atomic theory consisted of these 4 main points:
1) All matter is composed of small indestructible particles called atoms. They cannot be created or destroyed.
(2) All atoms of a given element are identical.
(3) Atoms of different elements have different properties
(4) In a chemical reaction atoms are separated, combined or rearranged, but maintain the law of conservation of mass.
True
How many hydrogen molecules are found in a 8.95 gram sample of hydrogen (H2)?
2.67 x 10^24 molecules