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