Which statement describes a concept included in the wave-mechanical model of an atom?
Electrons are located in regions called orbitals.
As an electron in atom moves from a higher energy state to a lower energy state, the atom
releases energy
Two atoms that are different isotopes of the same element have
same number protons, different number neutrons
The element in Group 14, Period 3, of the Periodic table is classified as a
metalloid (on or below the steps)
Which element has chemical properties that are most similar to potassium? (Choices: Cs, Ca, N, S)
Cesium (same group = similar properties)
Which element requires the least amount of energy to remove the most loosely held electron from a gaseous atom in ground state? (Choices: Na, Ar, P, Cl)
Na (lowest ionization energy)
Which terms identify two different categories of compounds?
ionic and molecular
Which statements describes the energy and bonding changes as two atoms of fluorine become a molecule of fluorine?
Energy is released as a bond is formed.
Which part of a calcium atom in ground state is represented by the dots in its Lewis electron-dot diagram?
the electrons in the fourth shell (valence electrons)
Based on Table S, an atom of which element has the strongest attraction for electrons in a chemical bond?
Chlorine (highest electronegativity)
Which substance can not be broken down by chemical means?
aluminum (because its an element)
Which statement describes the particles of an ideal gas, based on the kinetic molecular theory?
The volume of the gas particles is negligible compared with the total volume of the gas.
What is the amount of heat released by 1.00 gram of liquid water at degrees Celsius when it changes to a 1.00 gram of ice at 0 degrees Celsius?
334 J (Heat of Fusion)
Which term identifies a type of intermolecular force?
hydrogen bonding
Which statement describes a reaction at equilibrium?
The rate of formation of the products must equal the rate of formation of the reactants.
Entropy is a measure of
disorder of a system
Systems in nature tend to undergo change toward
lower energy and greater randomness
Which compound is an Arrhenius base? (Choices: HCl, H3PO4, Ca(OH)2, CH3COOH)
Ca(OH)2 (because base = OH)
In a neutralization reaction, an aqueous solution of an Arrhenius acid reacts with an aqueous solution of an Arrhenius base to produce
a salt and water
According to one acid-base theory, a base is an
H+ acceptor
Based on Table N, uranium-238 and uranium-235 have different
half-lives
A change in the nucleus of an atom that converted the atom from on element to another element is called
transmutation
Which radioactive emission has the greatest penetrating power but the least ionizing power?
gamma ray
Which statement describes a benefit of using fission reactions?
Large amounts of energy are produced per mole of reactant.
Which atom has a mass of 12u?
2.) E
Which electron configuration could represent the electrons in a sodium atom in an excited state?
4.) 2-7-2
What is the number of valence electrons in a nitrogen atom in the ground state?
5
Graphite and diamond are both solid forms of the element carbon. Which statement explain the different properties of these two forms of carbon?
Diamond has a different crystal structure from graphite.
A measured value for the atomic radius of platinum atoms was determined to be 143 picometers. Based on Table S, what is the percent error of this measured value?
10%
What is the chemical formula for sodium oxalate?
Na2C2O4
What is the molecular formula for this compound?
4.) C3H6
Which equation represents a single replacement reaction?
2) 2Al + 6HCl --> 2AlCL3 + 3H2
The bond between which two atoms is most polar?
H-O (greatest difference in electronegativities)
Which two gas samples contain equal numbers of atoms?
Helium and Argon
What occurs when Na2SO4 is added to this system, increasing the concentrations of SO4 2-?
Which numbered interval represents the heat of reaction?
2.
Based on Table J, which metal is more active than tin, but less active than zinc? (Choices: Ag, Cr, Cs, Mn)
2. Cr
What is the concentration of the KOH solution?
.0250 M
What is the unidentified element?
1.) L
Which type of reaction is represented by each of these equations?
Equation 1 represents fission and equation 2 represents fusion.