Study Chemistry Test Chapter 7

____ 42. The name of an oxyacid has the suffix -ic acid. What is the suffix of the oxyanion?

ate

21. Which is NOT a diatomic molecule?

boron

64. Chemical bond formation may take place due to the interaction between a(n) ____________________ and an anion.

cation

____ 37. Which is the correct name for the compound HClO3?

chloric acid

68. Electrons that are free to move in a metal are referred to as ____________________ electrons.

delocalized

____ 34. Which is the correct name for the compound N2O4?

dinitrogen tetroxide

____ 32. Which is the correct name for the compound N2O3?

dinitrogen trioxide

65. An ionic bond results due to the ____________________ attraction between two oppositely charged ions.

electrostatic

Indicate whether the statement is true or false. 4. In a correct Lewis structure, no atom can have more than eight valence electrons surrounding it.

false

43. Identify the correct structure of NO‾₃ .

has nitrogen in the middle surrounded by three oxygen atoms, two oxygen are surrounded by 6 valence electrons, total of 16 valence and a double bond occurs between one oxygen and nitrogen leading to 4 bonded valence and 2 lone pairs on one oxygen atom

Multiple Choice Identify the choice that best completes the statement or answers the question. ____ 5. Which is a property of substances that exhibit metallic bonding?

high boiling points

73. The name of the acid HI is ____________________ acid.

hydroiodic acid

38. Which is the correct name for the compound HNO2?

nitrous acid

70. When a chemical bond is formed, the constituent atoms acquire the valence electron configuration of noble gases called ____________________.

noble gas configuration

28. Based on its electronegativity difference, which kind of bond is present in the compound OF2?

nonpolar covalent

71. In naming the compound PCl , the prefix used with the second element is ____________________.

penta

66. The name of the anion is ____________________.

perchlorate

69. The name of the anion PO³-₄ is ____________________.

phosphate

____ 33. Which is the correct name for the compound PCl5?

phosphorus pentachloride

____ 22. Which type of bond has one pair of electrons shared between atoms?

single covalent

____ 31. What molecular shape does the compound CCl4 have?

tetrahedral

____ 29. Covalent compounds display which of these properties?

their intermolecular forces are relatively weak

72. The second part of the name of the compound NF is ____________________.

trifluoride

____ 20. Which type of molecular shape is shown by this molecule?

trigonal planar

Indicate whether the statement is true or false. 3. The breaking of covalent bonds requires the input of energy.

true

67. In the electron sea model, it is proposed that all the metal atoms in a metallic solid contribute their ____________________ electrons to form a sea of electrons.

valence

____ 24. How many single covalent bonds can halogens form?

1

____ 40. Fluorine belongs to group 7A. How many covalent bonds are formed between two fluorine atoms?

1

25. Multiple covalent bonds consist of which of these?

1 or 2 sigma bonds and a pi bond

___ 17. Which combination of bonds is present in this molecule? O = O

1 sigma bond and 1 pi bond

____ 41. How many pi bonds are there in a triple covalent bond?

2

____ 27. How many valence electrons are available in the ion NO3

24

____ 26. In the compound PCl3, how many total valence electrons are present?

26

____ 30. How many pairs of bonding electrons are in a molecule that displays sp2 hybridization?

3

____ 23. How many single covalent bonds can carbon form?

4

Essay 59. Explain why sulfur aluminide is not a correct name for the ionic compound formed between sulfur and aluminum

Aluminum comes first in bionamial nomenclature being that it is a nonmetal. It is a cation and doesn't end with the suffix -ide. Sulfur comes first in the name and ends with the suffix -ide.

____ 14. Which is the correct name for the compound NH4SO4?

Ammonium Sulfate

___ 19. Which covalent molecule has the strongest bond?

B

44. Which of the following compounds is an exception to the octet rule?

BH₃

53. The charge on the polyatomic ion, NO2, is 1-. What will be the formula of one formula unit of a compound between NO2 and Be?

Be (NO₂)₂

____ 6. Which is the correct formula for the compound formed between beryllium and nitrogen?

Be₃N₂

16. A formula unit of calcium bromide has two bromide ions corresponding to each calcium ion in the compound. What is the formula of calcium bromide? _ _

CaBr₂

46. In the equation for the formation of an ionic compound shown, what anion and cation will be formed? Give your answer in noble gas notation as well as by using the appropriate chemical symbol.

CaO

____ 11. Which is the correct name for the compound CaClO2?

Calcium chlorite

____ 13. Which is the correct name for the compound CoCO3?

Cobalt (II) Carbonate

____ 9. Which is the correct formula for the compound Chromium (II) Nitrate?

Cr(NO₃)₂

____ Indicate whether the statement is true or false. 2. A diatomic molecule is one that is made of only two different elements.

False

____ 39. Which is the correct formula for the compound phosphoric acid?

H₃PO₄

____ 10. Which is the correct name for the compound FeS?

Iron (II) Sulfide

Given the following ions, how many different ionic compounds are possible? List them with their names and their formulas.

Iron (II) phosphate, Iron (II) Phosphite, Iron (III) Phosphite, Iron (III) phosphate

52. Elements in groups 5A, 6A, and 7A in the periodic table form negatively charged ions by gain of electrons. What will be the charge on an atom, if it belongs to group 6A?

It will have a negative 2 charge.

51. Elements in groups 1A and 2A in the periodic table form positively charged ions by loss of electrons. What will be the charge on an atom, if it belongs to group 1A?

It will have a positive 1 charge.

61. Lithium is a reactive metal that reacts with oxygen to form an oxide. a. How many valence electrons does lithium have? b. How many electrons does lithium lose or gain to achieve a stable octet configuration? c. What is the formula of lithium oxide?

Lithium has 1 valence electron. It will lost 1 electron from 2s to achieve a stable octect configuration. The formula for lithium oxide is Li₂O.

56. Why is it necessary to use prefixes in naming covalent compounds?

Many covalent compounds contain the same elements and so numbers or quantities of elements in a compound must be represented in the name to differentiate them. Covalent compounds can form bonds in several different ratios to result in a chemically stable compound. Covalent compounds, unlike ionic compounds, have one ratio of ions that will result in a neutral compound. Therefore, the different ratios of atoms must be distinguished in some way. Prefixes are used in front of the element name to show how many equivalents of that element are present in a molecule of that compound.

49. Relate the hardness of metals to the number of delocalized electrons.

Metals with one valence electron tend to be soft. Metals with more valence electrons, as well as transition metals, are harder. D-block electrons are delocalized in a metallic bond, as well as s-block electrons. The more s and d block electrons in a metal, the harder the metal will be.

50. A metal, magnesium, forms an ion by losing three electrons. What will be the formula of one formula unit of the ionic compound between magnesium and oxygen?

MgO

7. What is the correct formula for the compound formed between magnesium and the phosphate ion?

Mg₃(PO₄)₂

____ 8. Which is the correct formula for the compound Manganese (III) Fluoride?

MnF₃

____ 15. The electron configuration of Na is [Ne]3s1 and that of Cl is [Ne]3s23p5 What is the formula of the compound when these elements react? a. Na Cl c. NaCl

NaCl

____ 35. Which is the correct formula for the compound dinitrogen monoxide?

N₂O

57. Ammonia is formed with one nitrogen and three hydrogen atoms. What is the electron configuration of nitrogen? How many lone pairs of electrons are present in nitrogen in an ammonia molecule?

One lone pair would exist for an ammonia molecule being that hydrogen requires two valence electrons to become stable and nitrogen requires 8. The electron configuration for nitrogen 1s²2s²2p³.

____ 36. Which is the formula for the compound sulfur hexachloride?

SCl₆

____ 12. Which is the correct name for the compound Na3P?

Sodium phosphide

58. The melting point of sugar is lower than that of common salt. What type of bonding can you predict for each compound? What type of force acts among the ions or molecules in the two compounds?

Sugar forms a covalent bond, whereas, common salt forms an ionic bond. Sugar has van der Walls forces, whereas, the force in common salt is ionic in nature.

____ 18. Which is true of the bond length of these covalent molecules?

The bonds in A are longer than the bonds in B or C

The molecule PCl3 has trigonal pyramidal shape, while the molecule BCl3 has trigonal planar shape. Explain why these molecules have such different shapes despite their similar formulas. Use Lewis structures to support your answer.

The difference is due to the unpaired electrons in PCl3. These cause additional repulsion, which makes the bonding electron pairs move farther away to minimize the repulsive effects. This causes the three sets of bonding electrons to be arranged all on one hemisphere of the central atom, resulting in the trigonal pyramidal shape. BCl3 does not have the unpaired electrons, so no additional repulsion occurs. Maximum separation of electrons occurs when the bonding pairs are at angles of 120 degrees from one another, which is a trigonal planar structure.

55. Which group on the periodic table generally has the highest electron affinity? Explain your answer in terms of atomic structure.

The halogens who contain 7 valence electrons in their outer shell have the highest electron affinity. The force of attraction between another electron is very strong compared to other groups. After gaining one electron, the anion will achieve noble-gas configuration.

48. Explain why it is not possible to write a correct chemical formula for the compound Copper Chloride. .

The oxidation number for copper is not given, so we must assume that the charge of copper is +1, which is not an existing oxidation number for copper. Copper is a transition element, which means that it may have more than one oxidation state. The oxidation state of the ion is usually represented in the name of the compound by using a Roman numeral in parentheses after the cation name. In this case, the compound could either be Copper (I) Chloride, or CuCl, or it could be Copper (II) Chloride, which is CuCl2.

Is this atom more likely to gain electrons or to lose electrons? Explain how you can tell.

This atom is most likely to gain electrons being that it has a set of 6 valence electrons. It will gladly receive two electrons from another atom to achieve noble-gas configuration. This atom would form an anion It would take a great deal more energy for this atom to lose 6 electrons to become stable. Gaining 2 electrons would require less energy.

Examine the Lewis structure below. If it is a correct structure for formaldehyde, CH2O, explain how it obeys the rules of drawing Lewis structures. If not, explain which rule(s) it does not follow and draw the correct structure.

This formeldahyde structure does not follow the octet rule. There are too many electrons present. 2 lone pairs must be deleted and a single bond must be added. Although each atom obeys the octet rule (except for H which does have 2 electrons), this is an incorrect structure. Since C contributes 4 valence electrons, O contributes 6, and each H contributes 1, there are a total of 12 valence electrons with which to form the structure. As drawn, there are 14 electrons being used. A Lewis structure can only be drawn with the available number of valence electrons. The correct structure is shown.

True/False Indicate whether the statement is true or false. ____ 1. Noble gases are generally non-reactive because they already have a complete valence shell.

True

54. Explain how electrostatic forces in two bonding atoms determines the bond length.

Two atom's bond is indicated by the bond length. A shorter bond length between two atoms often indicates a stronger attraction force between the two atoms and a longer wave length leading to a weaker, distant attraction between two atoms.The valence electrons of one atom are attracted to the positively charged nucleus of the other atom. However, the positively charged nuclei of each atom repel one another. If the atoms get too close, the nuclei repel one another; if they are too far apart, the valence electrons will be attracted to their opposite nucleus. This results in one specific distance between nuclei that is stable.

60. The electron configuration of zinc is 1s 2s 2p 3s 3p 4s 3d 3d . a. How many electrons are there in the outermost level? b. Which electrons are lost when zinc forms a bond? c. What is the charge on zinc when it loses electrons in forming a bond?

Zinc has 2 valence electrons in its outermost energy level. Zinc will lose 2 electrons from the 4s2 orbital. It will have a positive 2 charge when it loses 2 electrons