Chemistry Semester Test 2
Which diagram best represents the group and period trends in atomic radii in the periodic table?
(Figure C) Generally increase down groups, Generally decrease as you go across.
In an equation, the symbol for a substance in water solution is follwed by
(aq)
The oxidation number of fluorine is
-1 in all compounds
What is the electronegativity difference that usually is the dividing line between covalent and ionic bonds?
1.7
Because the first energy level contains only the 1s sublevel, the number of elements in this period is
2
How many pi bonds are there in a triple covalent bond
2
What is the balanced equation when aluminum reacts with copper(II) sulfate?
2Al + 3CuSO4 --> Al2(SO4)3 + 3Cu
Which equation is NOT balanced
2H2 + O2 ---> H2O
The electron configuration of nitrogen is 1s2 2s2 2p3. How many more electrons does nitrogen need to satisfy the octet rule
3
Bromine, atomic number 35, belongs to Group 17 (7A). How many electrons does bromine have in its outermost energy level?
7
The number of valence electrons in Group 17 (7A) elements is
7
How many electrons does an atom generally need in its outer level to be the most stable
8
In a molecule of fluorine, the two shared electrons give each fluorine atom how many electron(s) in the outer energy level?
8
What is the small whole number that appears in front of a formula in a chemical equation?
A coeffcient
What is the formula for aluminum sulfate
Al2(SO4)3
Name the compound Al2S3
Aluminum sulfide
Mendeleev noticed that properties of elements usually repeated at regular intervals when the elements were arranged in order of increasing
Atomic mass
Which of the following is NOT an example of a molecular formula
B
What is the formula of calcium phosphate, which is made up of the ions Ca2+ and PO4^3-? `
Ca3(PO4)2
A formula unit of calcium bromide has two bromide ions corresponding to each calcium ion in the the compound. What is the formula of calcium bromide?
CaBr2
What is the formula for the compound formed by calcium ions and chlride ions
CaCl2
Which observation does NOT indicate that a chemical reaction has occured?
Change in total mass of substances
How many electrons are shared in a double covalent bond?
Four
In writing a chemical equation that produces hydrogen gas, the correct representation of hydrogen gas is
H2
What is the formula for hydrochloric acid?
HCl
Refer to the figure below. To which group do fluorine and chlorine belong?
Halogens
Name the compound Fe(NO3)2
Iron (II) Nitrate
The person whose work led to a periodic table based on increasing atomic number was
Moseley
Identify the correct structure of NO3-
N in the center. 3 O's with four dots and two lines connecting them each to the N. One line is solid the other is dotted. (Figure D)
Which of the following molecules would be expected to have the greatest bond dissociation energy
N2
Name the compound Ni(ClO3)2
Nickle (II) chlorate
What is the formula for sulfur dichloride
SCl2
The element with electron configuration 1s2 2s2 2p6 3s2 3p2 is
Si (Z=14)
Which of the following relationships relating to bond length is generally correct
The shorter the bond, the stronger the bond
Name the compound Zn3(PO4)2
Zinc phosphate
An ionic bond is
a force that holds together atoms that are oppositely charged
Unequal sharing of electrons between two bonded atoms always indicates
a polar covalent bond
When a solid produced by a chemical reaction separates from the solution it is called
a precipitate
A polar molecule contains
a region of positive charge and a region of negative charge
In the equation 2Al(s) + 3Fe(NO3)2(aq) -> 3Fe(s) + 2Al(NO3)3(aq) iron has been replaced by
aluminum
According to the law of conservation of mass, the total mass of the reacting substances is
always equal to the total mass of the products
The most characteristic property of the noble gasses is that they
are largely un-reactive.
In metals, the valence electrons
are shared by all of the atoms
An element in the activity series can place any element
below it on the list
Name the compound CF4
carbon tetrafluoride
A positive ion is know as a(n)
cation
To balance a chemical equation, it may be necessary to adjust the
coeffcients
H+(aq) + Br-(aq) + K+(aq) + OH2(aq) -> H2O(l) + Br-(aq) + K+(aq) is an example of what type of chemical equation?
complete ionic
The equation AX --> A + X is the general equation for a
decomposition reaction
The reaction represented by the equation 2HgO(s) -> 2Hg(l) + O2 (g) is a(n)
decomposition reaction
The reaction represented by the equation 2KClO3(s) -> 2KCl(s) + 3O2(g) is a(n)
decomposition reaction
As atoms bond with each other, they
decrease their potential energy, thus creating more-stable arrangements of matter.
In a row in the periodic table, as the atomic number increases, the atomic radius generally
decreases
Four electrons are shared in a
double covalent bond
The equation AX + BY --> AY + BX is the general equation for a
double displacement reaction
The reaction represented by the equation Pb(NO3)2(aq) + 2KI(aq)--> PbI2(s) + 2KNO3(aq) is a
double displacement reaction
In metallic bonds, the mobile electrons surrounding the positive ions are called a(n)
electron sea
A measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound is called
electronegativity
A nonpolar covalent bond is one in which
electrons are shared equally
As you move left to right in Period 4 from gallium through bromine, atomic radii
generally decrease
As the atomic number of the metals of Group 1 (1A) increases, the ionic radius
increases
For each successive electron removed from an atom the ionization energy
increases
Salts are examples of
ionic compounds
In a crystal lattice of an ionic compound,
ions are surrounded by ions of the opposite charge
The formation of a stable ionic compound from ions
is always exothermic
The overall charge of a formula unit for an ionic compound
is always zero
Malleability and ductility are characteristic of substances with
metallic bonds
Elements in which the d-sublevel is being filled have the properties of
metals
Argon, Krypton, and Xenon are
noble gases
If two covalently bonded atoms are identical, the bond is
nonpolar covalent
Elements in the same group have the same
number of valence electrons
To draw a Lewis-dot structure, one must know the
number of valence electrons in each atom
If the s and p orbitals of the highest main energy level of an atom are filled with electrons, the atom has a(n)
octet
When determining the size of an atom by measuring the distance between bonded, identical, adjacent nuclei, the radius of an atom is
one-half the distance between the nuclei
Multiple covalent bonds may occur in atoms that contain carbon, nitrogen, or
oxygen
Identify the period and group of the element that has the electron configuration [Ne]3s2 3p3
period 3, group 15 (5A)
If the atoms that share electrons have an unequal attraction for the electrons, the bond is called
polar
Which of the following correctly describes the compound water, H2O?
polar overall, with polar covalent bonds.
Elements in a group or column in the periodic table can be expected to have similar
properties
The chemical formula for an ionic compound represents the
ratio of the combined ions present in a sample
In a crystal, the electrons of adjacent ions
repel each other
Identify the sublevels in a period that contains 32 elements
s, p, d, f
A chemical equation is balanced when the
same number of each kind of atom appears in the reactants and in the products
In the formation of a covalent bond, electrons are
shared
The formula unit of an ionic compound shows the
simplest ratio of the ions
The equation A + BX --> is the general equation for a
single displacement reaction
The reaction represented by the equation Cl2(g) + 2KBr(aq) -> 2KCl(aq) + Br2(l) is a(n)
single displacement reaction
The reaction represented by the equation Mg(s) + 2HCl(aq) -> H2(g) +MgCl2(aq) is a
single displacement reaction
A spoonful of sodium chloride is dissolved in a liter of water. What is sodium chloride in this solution?
solute
In an aqueous solution, water is the
solvent
The lattice energy is a measure of the
strength of an ionic bond
Name the compound SO3
sulfur trioxide
The equation A + X --> AX is the general equation for a
synthesis reaction
The reaction represented by the equation 2Mg(s) + O2(g) -> 2MgO(s) is a
synthesis reaction
The shape of a molecule whose central atom has four pairs of bonding electrons is
tetrahedral
VSPER theory is a model for predicting
the shape of molecules
How many chloride (Cl-) ions are present in a formula unit of magnesium chloride, given that the charge on a Mg ion is 2+
two
The bond angle is the angle between
two terminal atoms and the central atom
The electrons involved in the formation of a chemical bond are called
valence electrons
