Ch.2
A sample of copper has a mass of 56 grams. Determine the number of moles and the number of atoms in this sample.
(a) .88 mols of Cu
(b) 5.3 x 10^23 copper atoms
Calculate the energy of a photon with a wavelength of 450 nm. Express your answer in joules.
4.42 x 10^-19 J
Consider the element with the electron configuration Ar 4s² 3d¹⁰ 4p⁶. Determine its atomic number and provide its full chemical symbol.
Kr (atomic number = 36)
Classify the following as ionic or molecular: NaCl, H2SO4, NH4+
All ionic
Identify the common group of elements for each of the following: Strontium (Sr), Fluorine (F), and Xenon (Xe).
Using an energy level diagram, predict the relative change in energy when an electron transitions from n=4 to n=2
Energy is released
Arrange the following elements in order of increasing ionization energy: Lithium (Li), Beryllium (Be), and Boron (B).
Be < B < Li
If given the chemical formula Na2O, provide the systematic name.
Sodium Oxide
Identify the metalloid element present in period 3 of the periodic table and provide its atomic number.
Silicon (Si)
(a) Wavelength and Energy
(b) Frequency and Energy
(c) Wave and Energy Levels
(a) As wavelength increases = energy decreases
(b) As frequency increases = energy increases
(c) further apart energy levels = long wavelength/ shorter apart energy levels = short wavelengths
What is the Zeff of Aluminum (must show calculations)
3
Find the percent by mass of carbon in C6H12O6 (round up)
C = 40%
H = 7%
O = 53%
There are 3.50 moles of sulfur hexafluoride (SF₆). (Molar mass of SF₆ = 146.06 g/mol). Answer the following:
(a) Mass of sulfur hexafluoride
(b) Number of fluorine atoms
(a) 511 mol
(b) 1.26 x 10^25
Use quantum numbers to describe the location and shape of a 3d orbital in an atom. Include all relevant quantum numbers in your description.
n = 3
l = 2
ml = -2,-1,0,+1,+2
ms = -1/2 or +1/2
Arrange the following elements in order of increasing atomic radius: Oxygen (O), Neon (Ne), and Sulfur (S).
Ne < O < S
Identify the name represented by the formula Fe2(SO4)3.
Iron (lll) Sulfate
Given 2.50 moles of sodium (Na), calculate the number of atoms.
1.51 x 10^24
What are the 4 quantum numbers for 4p4 ?
n = 4
l = 2
ml = -2,-1,0,+1,+2
ms = -1/2 or +1/2
Rank the following elements in order of increasing electron affinity: Selenium (Se), Oxygen (O), and Fluorine (F).
Se < O < F
Provide the systematic name for N2O5.
Dinitrogen Pentoxide