Chemical Bonding Study Guide

Test Date: Wednesday, Feb. 1st

Name:______

  1. Write the electron configuration for each atom below and circle which ones are stable.
  1. Fe b. P3- c. Ar d. Cs1+

[Ar]4s23d6-not stable [Ne]3s23p6-stable [Ne] 3s23p6-stable [Xe]6s2-not stable

  1. Circle the atoms below that are stable.
  1. Cu b. Zn2+ c. Ne d. F1+ e. Pb2+ f. S2-

Not stable stable stable not stable stable stable

  1. What is the Octet Rule? Elements that are not naturally stable will become stable by gaining (anions), losing (cations), or sharing valence electrons. (Most elements outer s and p-orbitals filled).
  2. What is an oxidation number? The charge on an atom when it becomes stable.
  3. Why are compounds more common in nature than elements? Elements within a compound are more stable than when they exist as an element.
  4. Determine if the following are monatomic or polyatomic ions.
  1. (OH)- b. Cl- c. sulfate ion d. sulfide ion

Poly mono poly(-ate ending) mono (-ide ending)

  1. Why are ionic compounds neutral? Because the ions making up the compound combine in such a ratio that the overall charge on the compound is zero.
  2. What is a molecule? A compound that consists of only non-metals = covalent compound
  3. Draw the Lewis dot transfer between Ca and P. When you draw the Lewis Dot structure you should get the following ratio of ions: Ca2P3
  4. Determine which compounds below are ionic and which are covalent , and then give the chemical name of each.

a. CCl4 : covalent, carbon tetrachloride

b. Fe(OH)3 : ionic, iron (III) hydroxide

c. SrS : ionic: strontium sulfide

d. N2 : covalent; nitrogen

e. PCl5 : covalent phosphorus pentachloride

f. Ca3P2 : ionic; calcium phosphide

11. Determine which compounds below are ionic and which are covalent, and give the chemical formula of each.

a. oxygen disulfide: covalent: OS2

b. beryillium nitride: ionic; Be3N2

c. hydrogen: covalent; H2

d. Chromium (III) nitrate : ionic Cr(NO3)3

12. Circle the ionic compounds below that would occur in nature. (would form to reach stability)

a. magnesium phosphide b. copper (II) calcide c. FeAr d. V(PO4)

could occur in nature could not(2 metals) could not (noble gas) could occur in nature

13. a. What is a diatomic molecule? Usually two atoms of the same element.

b. What are the seven diatomic molecules?

H2, N2, O2, F2, Cl2, Br2, I2

14. What is electronegativity? The degree of attraction one element has for another element’s valence electrons.

15. Use the graph below to answer questions on electronegativity.

  1. What is the trend (pattern) for electronegativity across a period? Increases, except noble gases
  2. What is the trend (pattern) for electronegativity down a group? Decreases
  3. Rank the following elements in increasing order based on electronegativity.

N, Ne, B, Li (same period) Ne, Li, B, N

d. According to the graph, would ionic compounds or covalent compounds have a larger electronegativity difference? Ionic compounds, because the atoms consisting an ionic bond have very large differences in electronegativity values: metal and a nonmetal, compared to covalent compounds where they consists of non-metals with closer electronegativity values.

  1. Complete the table below on covalent compounds.

Cannot draw molecular structures on computer, so if have question must ask tomorrow.

Molecular Formula / Electron Dot Sharing / Molecular Structure / Polar or Non-Polar Bonds
Br2 / Br-Br: non-polar bond
(Sharing the paired e- equally)
P2 / P-P: non-polar bond
Sharing the paired electrons equally
NH3 / N-H: polar bond
Do not share the paired electrons equally
SiF4 / Si-F: polar bond
Do not share the paired electrons equally

17. Determine which molecules above would have the following:

a. single bond molecules: Br2, SiF4, and NH3 b. double bond molecules: none c. triple bond: P2

18. What is the difference between polar covalent compounds and ionic compounds?

Polar covalent: unequal sharing of paired valence electrons, causing partial charges between the atoms

Ionic compounds: transfer of valence electrons, causing full charges (cation and anion)

19. Circle the compound in each example below that makes the statement true.

a. Would NaF or CH4 conduct electricity when dissolved in water? Explain your answer.

An ionic compound would conduct electricity, so it will be NaF because it is an ionic compound.

b. Is LiBr or P2O5 crystal lattice more brittle when stress is applied to it? Explain your answer.

Ionic compound’s crystal lattice is more brittle because it is composed of charged ions that must be aligned to minimize repulsion. If stress is applied and the crystal lattice of the ions is shifted where repulsion force is greater the compound will break or crack. Therefore, LiBr is more brittle because it is an ionic compound.

c. Would C6H12O6 or Na(HCO3) crystal lattice grow faster? Explain your answer.

From the lab, we observed that ionic compounds grew faster because they consist of charged ions that are strongly attracted to one another. Since Na(HCO3) is ionic it will grow faster. Sugar, C6H12O6, is composed of neutral compounds and therefore will not form the crystal structure as quick.

e. Does Ca3N2 or CF4 have a lower melting point? Explain your answer.

Ionic compounds have a higher bond strength which we said is directly related to a higher melting point. Why? Again, because they are composed of charged ions that are strongly attracted to one another. Therefore, CF4, should have a lower melting point because it is a covalent compound instead of an ionic compound.

20 . Label the following statements as either ionic or covalent.

  1. Transfer of valence electrons to reach stability-Ionic
  2. Prefixes are included with chemical name.-Covalent
  3. –ate or –ite endings –Ionic (polyatomic ions)
  4. Crystal lattice composed of ions: Ionic
  5. Sharing of valence electrons to reach stability: Covalent
  6. Roman numerals might be included with chemical name: Ionic (metals with multiple charges)
  7. Crystal lattice composed of neutral atoms: Covalent
  8. Compounds composed of non-metals only: Covalent
  9. Compounds that have higher melting points: Ionic
  10. Compounds that cannot conduct electricity when dissolved in water.: Covalent
  11. Compounds that are composed of usually a metal and a non-metal.: Ionic
  12. Compounds that can conduct electricity when dissolved in water. : Ionic

*Make sure you know prefixes for covalent compounds.