For the pair of atoms, which has the largest radius and greatest electronegativity:
Aluminum and Indium
Aluminum has the greatest electronegativity
Indium has the largest radius
200
What is the name of SCl2? Is SCl2 ionic or covalent? What is the geometry of SCl2?
Sulfur dichloride, covalent, bent.
300
Are changes of state a physical or chemical change? Describe the difference between a physical and chemical change.
Physical change. A chemical change changes the chemical composition of the original substance.
300
How many valence electrons does the following element have:
[Kr]5s2 4d10 5p5
What family is this element in?
7, Halogens
300
Marie Curie, the first woman to win a Nobel Prize and the first person to win two Nobel prizes, later died as a result of exposure to the radioactivity she spent her life researching. Which form of radioactive decay has the highest penetrating power?
Gamma radiation
300
Comparing N to its ion, N3-, which has the largest radius? Why?
The ion N3- has the largest radius because it gains 3 electrons which repel each other and make the radius larger.
300
What is the chemical formula for nickel(II) acetate? Is nickel(II) acetate ionic or covalent? What is the geometry of nickel(II) acetate?
Ni(CH3COO)2, ionic, lattice
400
Otis was examining separation processes. In his attempts to separate the sodium and chlorine in salt he attempted numerous methods including filtering, decanting, evaporation, and distillation. All of these attempts fail for a variety of reasons. What is the most likely explanation for why these attempts failed?
Sodium chloride is a compound that can be separated only through a chemical reaction.
400
What did the following scientists contribute to the development of atomic theory:
Dalton, Thomson, Rutherford, and Bohr
Dalton: Postulates of Atomic Theory
Thomson: Discovered electron, used plum pudding model
Rutherford: Discovered positively charged nucleus, Used gold foil and detector ring
Bohr: Discovered electrons reside in energy levels with discrete amounts of energy
400
Blue light has a frequency of 6.98 x 10^14 Hertz. Calculate the wavelength and energy of blue light.
Wavelength: 4.30 x 10^-7 meters
Energy: 4.63 x 10^-19 Joules
400
By the late 1800's, scientific research had developed to the point that Dmitri Mendeleev published a periodic table using what properties to order elements?
Elements were shown in vertical columns of similar chemical and physical properties and rows ordered by increasing mass.
400
Draw the electron dot structure for CI4. What is the geometry of CI4?
I
I C I
I
Tetrahedral
500
When sample X is passed through a filter paper, a white residue (Y), remains on the filter paper and a clear liquid (Z) passes through. When the liquid is vaporized, another white residue remains. Starting sample X is best classified as a:
A heterogeneous mixture.
500
Element X has two naturally occurring isotopes:
1) 78.91 amu, 50.75% abundance
2) 80.92 amu, 49.25% abundance
Calculate the average atomic mass for element X. Identify element X.
79.90 amu, Bromine
500
Provide balanced nuclear reactions for each of the following:
1) the alpha decay of Polonium-208.
2) the beta decay of Potassium-40.
3) the gamma decay of Cobalt-60.
Identify which of the following elements is least reactive with water and which is most reactive with water. Explain why this order of increased reactivity exists in terms of ionization energy.
Magnesium, Sodium, and Potassium
Magnesium, Sodium, and Potassium
Sodium and potassium have 1 valence electron and are more reactive than magnesium with 2 valence electrons.
Potassium is the most reactive because it has the lowest ionization energy meaning that it takes less energy to remove its valence electron.
500
How does the geometric shape change in a molecule with three atoms when a lone pair of electrons is added?
It changes from trigonal planar to trigonal pyramidal.