Chemistry Chapter 7 Quiz

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Questions and Answers

Which statement accurately describes the solubility of substances?

All ionic substances are non-polar.

Non-polar substances can only dissolve polar substances.

Polar substances can dissolve both polar and non-polar substances.

Polar substances dissolve polar substances and non-polar substances dissolve other non-polar substances. (correct)

What characterizes metallic bonding?

It involves the sharing of electrons between two non-metals.

It is characterized by free-floating valence electrons around positive metal ions. (correct)

It primarily occurs between polar covalent molecules.

It consists of attraction between positive metal ions and surrounding non-polar molecules.

Which of the following is a correct example of a polar covalent molecule?

O2 (oxygen)

CH4 (methane)

HCl (hydrochloric acid) (correct)

C6H12O6 (glucose)

What molecule is an example of a non-polar covalent substance?

CCl4 (carbon tetrachloride) Signup and view all the answers

Which property is NOT associated with covalent bonds?

Formation of metallic lattices. Signup and view all the answers

What characterizes a coordinate (dative) covalent bond?

Both electrons in the shared pair come from the same atom. Signup and view all the answers

In the Lewis structure of carbon dioxide (CO2), how many total lone pairs are present?

0 Signup and view all the answers

Which statement accurately describes polarity in molecules?

A nonpolar molecule has an equal distribution of charge among its atoms. Signup and view all the answers

In a Lewis structure, which of the following correctly depicts bonded pairs between atoms?

Bonded pairs are represented by lines or pairs of dots between atoms. Signup and view all the answers

Which of the following substances exhibits a coordinate covalent bond?

Ammonia (NH3) when donating a lone pair to H+ Signup and view all the answers

What is the correct prefix for a molecule containing three atoms of an element?

Tri Signup and view all the answers

Which of the following molecules is named using a special name rather than the systematic naming system?

CH4 Signup and view all the answers

Which suffix indicates that a molecule contains only two types of atoms?

-ide Signup and view all the answers

What is a lone pair?

Electrons that are not involved in bonding Signup and view all the answers

What is the correct name for the molecule H2O?

Water Signup and view all the answers

What is the prefix for a molecule that contains four atoms of an element?

Tetra Signup and view all the answers

Which of the following represents a coordinate covalent bond?

A nitrogen atom donating two electrons to a hydrogen ion Signup and view all the answers

Which of the following molecules is likely to be polar?

H2O Signup and view all the answers

Study Notes

Chemical Bonding

Chemical reactions cause elements to bond to gain stability.
Elements bond chemically to form a full octet of electrons (octet rule).
The first four elements have an octet of 2 electrons.
All other elements gain stability by gaining 8 valence electrons.
Electronic configuration rules:
- First shell holds 2 electrons.
- Second shell holds 8 electrons.
- Third shell holds 8 electrons.
- Fourth shell up to 32 electrons.
Elements bond to gain stability.
Elements in groups 1-7 will bond to gain stability.
Elements in group 8 are stable and don't bond (inert/unreactive). They already have a full octet of valence electrons.
Elements bond to gain stability (full octet of valence electrons).
Valence electrons participate in chemical bonding.
Valence electrons are electrons in the outermost shell of an atom.
Protons and neutrons are in the nucleus, they do not participate in chemical bonding.
Types of chemical bonds:
- Ionic
- Covalent
- Metallic

Ionic Bonding

Ionic bonds form between metal and nonmetal atoms.
Metal atoms donate valence electrons to nonmetal atoms.
Metal atoms become positively charged ions (cations).
Nonmetal atoms accept valence electrons and become negatively charged ions (anions).
Ionic bonds involve the electrostatic attraction between oppositely charged ions.
Elements in groups 1 (alkali metals) and 2 (alkaline earth metals) are commonly used in ionic bonding.
Hydrogen, though in group 1, is a nonmetal.
Boron, though in group 3, is a metalloid, not a metal.
Transition metals (elements 21-30) are not used in ionic bonding.
The substance formed is called a compound.
Compounds have a fixed ratio of elements.
Compounds have a special name called a formula unit.

Steps in Ionic Bonding

Write electronic configurations of the atoms.
Determine if the atoms are a metal or a nonmetal.
Draw the structures. Use dots for metal electrons and crosses for nonmetal electrons.
Transfer valence electrons between atoms. Use arrows. Ensure both atoms become stable (metal has lost all outer electrons and nonmetal has gain 8 outer electrons).
Redraw the structures. Place the charges in the top right corner of the atoms.
Write the formula and the name.

How to write chemical formulas and formula names for ionic substances

Write the symbol of the nonmetal first, and write the number to the right of the nonmetal representing the number of atoms.
Write the symbol of the metal second, and write the number representing the number of atoms.
To name the ionic substance: Write the name of the metal first, and write the name of the nonmetal second, but changing the ending of the nonmetal to "ide." Example: Chlorine becomes chloride.

Covalent Bonding

Covalent bonding occurs between nonmetal atoms.
Atoms share valence electrons.
Molecules are formed.
The molecules formed are called covalent molecules.
Types of covalent bonds:
- Single bond (sharing 1 pair of electrons)
- Double bond (sharing 2 pairs of electrons)
- Triple bond (sharing 3 pairs of electrons)

Steps in Covalent Bonding

Write the electronic configuration of your atoms.
Determine if your atoms are a metal or a nonmetal. Both atoms must be nonmetals.
Draw structures. Use dots for one atom and crosses to represent electrons.
Place largest atom in the center. Place surrounding atoms around the central atom, sharing pairs of electrons with the central atom.
Share valence electrons between atoms to form bonds. Make sure the atoms are stable (8 electrons in their valence shell). If not, try using double or triple bonds.
Redraw the new structures (show the new electronic configurations) in brackets, and indicate the charge in the top right of atoms.
Write the chemical formula and give the name.

How to write the chemical formulas and formula names for covalent substances

Assess the structure to find how each element exists.
Write the formula by writing the symbol of the central atom/atoms first, and noncentral atoms. Use subscripts to indicate the number of atoms for each element.
Write the name by applying learned prefixes.
Change the suffix for the second element to “ide.”

Covalent Bond Prefixes

Number of AtomsPrefix1Mono2Di3Tri4Tetra or Tetr5Pent6Hex7Hept8Oct

Other covalent compounds

Some covalent compounds have special names based on historical usage.
Example: Water (H₂O), Ammonia (NH₃).

Lone Pairs

Lone pairs are valence electrons not involved in bonding.
Lone pairs do affect the geometry.
Lone pairs are important to chemical reactions, even if they are not bonded.

Lewis Structures

Lewis structures illustrate atoms and their bonds in a molecule.
Show pairs of electrons, whether bonding or lone.

Metallic Bonding

Metallic bonds form between metal atoms.
Valence electrons are delocalized (free to move).
Metal ions are positively charged.
Electrons share between metal ions.
Asea of mobile electrons surrounds positive metal ions.

Metallic Properties

Positive metal cations in a sea of mobile electrons.
Electrons shared amongst all metal ions.
Leads to a metallic lattice.

Polarity

Some molecules are polar, which means they have positive and negative charges.
Polar molecules arise when one atom exerts a stronger attractive force on the electrons in a bond.
The electrons are pulled toward the atom with the stronger attractive force.
Polarity is caused by differences in electronegativity.
Like dissolves like.

Electronegativity

Electronegativity is a measure of an atom's ability to attract electrons.
The difference in electronegativity between two atoms indicates the type of bond.
A small difference indicates a nonpolar covalent bond. A large difference indicates a polar covalent or ionic bond. (Refer to table for electronegativity ranges).

Summary of Chemical Bonds and Types

Type of BondAtoms InvolvedElectrons UsedHow Electrons are SharedExampleIonic BondMetal and non-metalElectrons transferredFull 'transfer' of electrons resulting in opposite charges; electrostatic attractionNaCl (sodium chloride)Covalent BondNon-metalsElectrons sharedSharing electrons to form pairs; attraction between shared electrons and both atomic nuclei.H₂O (water)Metallic BondMetalsElectrons delocalized/ free-floatingSea of mobile electrons that surround positive metal cations.Na (sodium)

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Description

Test your understanding of solubility, bonding types, and molecular structure in this Chemistry Chapter 7 quiz. Questions cover topics such as polar and non-polar covalent bonds, metallic bonding, and the Lewis structure of molecules. This quiz is perfect for students looking to reinforce their knowledge in chemistry.