Module 3

The table provides the number of valence electrons for each of the two atoms that form an ionic and a covalent compound. Which of the following statements is true about one of the compounds? (4 points) Compound C is ionic because both atoms are in need of electrons. Compound D is covalent because both atoms are in need of electrons. Compound D is ionic because one atom is in need of electrons and the other needs to lose electrons. Compound C is covalent because one atom is in need of electrons and the other needs to lose electrons.

Compound D is covalent because both atoms are in need of electrons.

What is the formula unit for a compound made from Ca and O? (5 points) CaO2 because the total negative charge on O is two. Ca2O because the total negative charge on Ca is one. CaO because the total positive charge on O is one. CaO because the total positive charge on Ca is two.

CaO because the total positive charge on Ca is two.

What best describes the bonding in a carbon dioxide molecule? (5 points) Carbon shares two of its electrons, and each oxygen shares four of its electrons. Carbon shares four of its electrons, and each oxygen shares two of its electrons. Carbon receives two electrons from each of the two oxygen atoms. Carbon transfers two electrons to each of the two oxygen atoms.

Carbon shares four of its electrons, and each oxygen shares two of its electrons.

What is the correct name for CH4? (3 points) Carbon tetrahydride Carbon (IV) hydride Monocarbon tetrahydride Monocarbon hydroxide

Carbon tetrahydride

An atom's Lewis dot structure has four dots. Which of the following elements could it be, and why? (4 points) Aluminum, because it is a metal with four electrons in period 3. Beryllium, because it is in period 2 and has four total electrons. Carbon, because it is in group 14 and has four valence electrons. Calcium, because it is an alkaline earth metal in period 4.

Carbon, because it is in group 14 and has four valence electrons.

Consider the molecules H2O, H2S, H2Se, and H2Te. Which do you expect to have the highest boiling point, and why? (4 points) H2O, because it experiences hydrogen bonding. H2S, because it dissociates and forms ions. H2Se, because it experiences ion-dipole forces. H2Te, because it has the most electrons to form a dipole.

H2O, because it experiences hydrogen bonding.

An induced dipole occurs when a molecule's moving electrons are briefly more concentrated in one place than another, causing the molecule to become temporarily polarized. (4 points) True False

False

Lithium has a 1+ charge, and oxygen has a 2− charge. A Lewis dot diagram should contain one lithium atom and two oxygen atoms to show how these atoms form an ionic bond. (1 point) True False

False

Sulfur hexachloride is an ionic compound. (3 points) True False

False

The molecule CCl4 contains one double bond and three single bonds. (2 points) True False

False

What is the formula unit for a compound made from Fe2+ and oxygen? (3 points) OFe FeO Fe2O O2Fe

FeO

Which of the following best represents and explains the formula for a compound made from fluorine and hydrogen? (5 points) HF, because both fluorine and hydrogen are capable of forming only one ionic bond. HF, because both fluorine and hydrogen are capable of forming only one covalent bond. H2F, because fluorine is short of two electrons, and hydrogen is short of one electron. H2F, because fluorine is capable of forming one, and hydrogen is capable of forming two covalent bonds.

HF, because both fluorine and hydrogen are capable of forming only one covalent bond.

The Lewis dot notation for two atoms is shown.What is represented by this notation? (5 points) Na loses one proton to Cl. Na loses one electron to Cl. Na gains two protons from Cl. Na gains one electron from Cl.

Na loses one electron to Cl.

What does the first word in the name of a binary ionic compound represent? (5 points) The non-metal The negative ion The positive ion The gaseous element

The positive ion

Look at the image shown.What does this image represent? (5 points) Linear molecule with one domain Linear molecule with two domains Tetrahedral molecule with four domains Trigonal planar molecule with three domains

Trigonal planar molecule with three domains

Valence electrons are involved in chemical bonding. (3 points) True False

True

What is the charge on an atom after it gains two electrons during the formation of a bond? (5 points) One positive charge Two positive charges Two negative charges One negative charge

Two negative charges

Match the formula to the correct name. (3 points) Al2O3 Al(HCO3)3 Al2(CO3)3 a.Aluminum oxide b.Aluminum bicarbonate c.Aluminum carbonate

a, c, b

Match each element to the number of electrons in its valence shell. (4 points) Magnesium (Mg) Oxygen (O) Hydrogen (H) Carbon (C) a.Four b.One c.Two d.Six

c, d, b, a

Match each of the unknown ions to its appropriate description. (4 points) Z2− V2+ Y3− X3+ a.A metal that lost two electrons b.A metal that lost three electrons c.A nonmetal that gained three electrons d.A nonmetal that gained two electrons

d, a, c, b

An atom has the following electron configuration. 1s22s22p63s23p4 How many valence electrons does this atom have? (4 points) 2 4 6 12

6

When two fluorine atoms bond together in F2, what type of covalent bond do they form? (4 points) A double bond, because they overlap orbitals to share one pair of electrons. A double bond, because they overlap orbitals to share two pairs of electrons. A single bond, because they overlap orbitals to share one pair of electrons. A single bond, because they overlap orbitals to share two pairs of electrons.

A single bond, because they overlap orbitals to share one pair of electrons.

Which of the following is a correct formula unit of an ionic compound? (3 points) Al2O3 Ca2O MgOH NaCl2

Al2O3

What is the name of a compound having the formula Al2O3? (5 points) Aluminum peroxide Aluminum ozone Aluminum oxygen Aluminum oxide

Aluminum oxide

A student made the Lewis dot diagram of a compound as shown.What is the error in the Lewis dot diagram? (3 points) An O atom should transfer all its six electrons to Mg because the formula is MgO. Both electrons of Mg should be transferred to one O atom because the formula is MgO. The electrons should be transferred from each O atom to Mg because Mg has fewer electrons. The number of dots around Mg should be four because it has to transfer two electrons to each O.

Both electrons of Mg should be transferred to one O atom because the formula is MgO.

What is the strongest intermolecular force that occurs between molecules of H2S? (4 points) Covalent bonding Dipole-dipole force Hydrogen bonding London dispersion force

Dipole-dipole force

What type of intermolecular force occurs between polar molecules? (4 points) Dipole-dipole force Hydrogen bonding Induced dipole force Polar covalent bonding

Dipole-dipole force

Which of the following are electrostatic interactions of permanent dipoles in polar molecules? (5 points) Ion-dipole forces Hydrogen bonding Dipole-dipole forces London dispersion forces

Dipole-dipole forces

Which phrase best describes the bond in O2? (5 points) Double covalent bond Single covalent bond Double ionic bond Single ionic bond

Double covalent bond

Look at this image.What do the lines in this image represent? (5 points) Ionic bonds between carbon and oxygen Non-bonded valence electrons of oxygen Double covalent bonds in carbon dioxide Valence electrons donated in carbon dioxide

Double covalent bonds in carbon dioxide

A double covalent bond involves two atoms sharing two electrons. (2 points) True False

False

Which of the following explains the VSEPR geometry of a carbon tetrachloride molecule? (5 points) It is bent because there are four bonded pairs around carbon. It is tetrahedral because there are four bonded pairs around carbon. It is bent because there are two bonded pairs and two lone pairs around carbon. It is tetrahedral because there are two bonded pairs and two lone pairs around carbon.

It is tetrahedral because there are four bonded pairs around carbon.

The boiling point of water (H2O) is 100 °C. Which of the following best predicts the boiling point of hydrogen sulfide (H2S)? (5 points) Higher than 100 °C because ion dipole interactions in hydrogen sulfide are stronger than hydrogen bonding in water. Lower than 100 °C because hydrogen sulfide has dipole-dipole interactions instead of hydrogen bonding. Lower than 100 °C because the hydrogen bonding in hydrogen sulfide is weaker than it is in water. Higher than 100 °C because the size of a sulfur atom is larger than the size of an oxygen atom.

Lower than 100 °C because hydrogen sulfide has dipole-dipole interactions instead of hydrogen bonding.

What is the correct name for Hg(NO3)2? (3 points) Mercury (I) nitrate Mercury (II) nitrate Mercury nitroxide Mercury dinitride

Mercury (II) nitrate

What is the formula for magnesium sulfate? (3 points) MgS Mg2S MgSO3 MgSO4

MgSO4

What is the formula of the compound formed between oxygen (O) and sodium (Na)? (3 points) ONa, because oxygen gains one electron and sodium loses one electron. ONa2, because oxygen gains two electrons and sodium loses one electron. Na2O, because oxygen gains two electrons and sodium loses one electron. NaO, because oxygen gains one electron and sodium loses one electron.

Na2O, because oxygen gains two electrons and sodium loses one electron.

What types of atoms typically form covalent bonds? (4 points) Metals with nonmetals, because their difference in electronegativity is above 1.7. Metals with nonmetals, because their difference in electronegativity is below 1.7. Nonmetals with nonmetals, because their difference in electronegativity is above 1.7. Nonmetals with nonmetals, because their difference in electronegativity is below 1.7.

Nonmetals with nonmetals, because their difference in electronegativity is below 1.7.

Two students made the Lewis dot diagrams of H2O. The diagrams are as shown.Which student drew the correct Lewis dot diagram? (4 points) Only Student A Only Student B Both Student A and Student B Neither Student A nor Student B

Only Student A

What type of ions do metals naturally form? (3 points) Negative ions, by gaining electrons to fill the valence shell Negative ions, by losing electrons to empty the valence shell Positive ions, by gaining electrons to fill the valence shell Positive ions, by losing electrons to empty the valence shell

Positive ions, by losing electrons to empty the valence shell

What happens when the compound NaCl is formed? (5 points) Sodium transfers an electron to chlorine. Sodium receives two electrons from chlorine. Sodium forms an ion with −1 charge and chlorine forms an ion with +1 charge. Sodium forms an ion with +2 charge and chlorine forms an ion with −2 charge.

Sodium transfers an electron to chlorine.

The boiling points of diatomic halogens are compared in the table. Which of the following statements best explains the trends in boiling points? (4 points) The atomic size increases down the group, and this decreases the strength of the intermolecular forces. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.