Chemistry Chapter 9 Flashcards
44 Questions
100 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

A structural formula shows the arrangement of the atoms in a molecule.

True (A)

The central atom in a molecule is the one with the highest electron affinity.

False (B)

In molecules, hydrogen is always a terminal atom.

True (A)

The number of bonding pairs in a molecule is equal to the number of electrons.

<p>False (B)</p> Signup and view all the answers

To find the total number of electrons available for bonding in a positive ion, you should add the ion charge to the total number of valence electrons of the atoms present.

<p>False (B)</p> Signup and view all the answers

The electrons in a coordinate covalent bond are donated by both bonded atoms.

<p>False (B)</p> Signup and view all the answers

Resonance occurs when more than one valid Lewis structure can be written for a molecule.

<p>True (A)</p> Signup and view all the answers

Nitrate is an example of an ion that forms resonance structures.

<p>True (A)</p> Signup and view all the answers

The carbon dioxide molecule contains two double bonds.

<p>True (A)</p> Signup and view all the answers

All electrons in an atom are available for bonding.

<p>False (B)</p> Signup and view all the answers

In the sulfate ion (SO4 2-), 32 electrons are available for bonding.

<p>True (A)</p> Signup and view all the answers

When carbon and oxygen bond, the molecule contains ten pairs of bonding electrons.

<p>False (B)</p> Signup and view all the answers

Identify the molecule with an odd number of valence electrons.

<p>NO</p> Signup and view all the answers

Identify the molecule with fewer than 8 electrons around an atom.

<p>BF3</p> Signup and view all the answers

Identify the molecule with more than 8 electrons around the central atom.

<p>SF6</p> Signup and view all the answers

Identify the molecule that has more than one valid Lewis structure.

<p>O3</p> Signup and view all the answers

The VSEPR model is used mainly to determine what?

<p>molecular shape</p> Signup and view all the answers

What is the bond angle?

<p>the angle between two terminal atoms and the central atom</p> Signup and view all the answers

What is the basis of the VSEPR model?

<p>shared and unshared electron pairs repel each other as much as possible</p> Signup and view all the answers

What is the shape of a molecule whose central atom has four pairs of bonding electrons?

<p>tetrahedral</p> Signup and view all the answers

What is the shape of a molecule that has two covalent single bonds and no lone pairs on the central atom?

<p>linear</p> Signup and view all the answers

What is the shape of a molecule that has three single covalent bonds and one lone pair on the central atom?

<p>trigonal pyramidal</p> Signup and view all the answers

The formation of new orbitals from a combination or rearrangement of valence electrons is called __.

<p>hybridization</p> Signup and view all the answers

The orbitals that are produced through hybridization are __ to one another.

<p>identical</p> Signup and view all the answers

An example of an element that commonly undergoes hybridization is __.

<p>carbon</p> Signup and view all the answers

When carbon combines three p orbitals and its one s orbital, the orbitals that result are called __.

<p>sp3</p> Signup and view all the answers

An example of a molecule that has sp3 is __.

<p>methane</p> Signup and view all the answers

What is the meaning of the term electronegativity?

<p>Indicates the relative ability of an element's atoms to attract electrons in a chemical bond</p> Signup and view all the answers

Which element has the highest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the highest overall electronegativities?

<p>Fluorine, 3.98, halogen, group 7A</p> Signup and view all the answers

Which element has the lowest electronegativity? What is the numerical value? What are the name and group number of the chemical family that has the lowest overall electronegativities?

<p>Francium, 0.7, alkali metals, group 1A</p> Signup and view all the answers

What general trend in electronegativity do you note going down a group? Across a period?

<p>Going down it gets lower, going right it gets higher</p> Signup and view all the answers

How are the electronegativity values used to determine the type of bond that exists between two atoms?

<p>You're going to take the difference</p> Signup and view all the answers

Ionic compounds are usually soluble in polar substances.

<p>True (A)</p> Signup and view all the answers

In a covalent molecular compound, the attraction between molecules tends to be strong.

<p>False (B)</p> Signup and view all the answers

Unequal sharing of electrons between two bonded atoms always indicates what?

<p>a polar covalent bond</p> Signup and view all the answers

When electronegativities of two bonded atoms differ greatly, the bond is what?

<p>ionic</p> Signup and view all the answers

What is the electronegativity difference that usually is the dividing line between covalent and ionic bonds?

<p>1.7</p> Signup and view all the answers

The symbol delta is placed next to what?

<p>the less electronegative atom in a polar covalent bond</p> Signup and view all the answers

A nonpolar covalent bond is one in which?

<p>electrons are shared equally</p> Signup and view all the answers

Molecules containing only polar covalent bonds?

<p>may or may not be polar</p> Signup and view all the answers

What factor other than electronegativity determines whether a molecule as a whole is polar or not?

<p>its geometry</p> Signup and view all the answers

What correctly describes the compound water H2O?

<p>polar overall, with polar covalent bonds</p> Signup and view all the answers

What correctly describes the compound carbon tetrachloride, CCl4?

<p>nonpolar overall, with polar covalent bonds</p> Signup and view all the answers

A molecule of ammonia, NH3, is?

<p>polar because there is an electronegativity difference and the molecule is trigonal pyramidal</p> Signup and view all the answers

Study Notes

Structural Formulas and Bonding

  • A structural formula illustrates the arrangement of atoms within a molecule.
  • In a molecule, hydrogen atoms are always positioned as terminal atoms.
  • The number of bonding pairs does not equal the total number of electrons in a molecule.
  • The electrons in a coordinate covalent bond are only donated by one atom, not both.

Resonance and Molecular Structures

  • Resonance occurs when multiple valid Lewis structures can be created for a single molecule.
  • Nitrate (NO3-) is an example of an ion that can have resonance structures.
  • Carbon dioxide (CO2) contains two double bonds, contributing to its linear structure.

Bonding Electrons and Ions

  • In the sulfate ion (SO4 2-), a total of 32 electrons are available for bonding.
  • Electrons in an atom are not all available for bonding due to filled electron shells.

Molecular Geometry and VSEPR Theory

  • The VSEPR model is utilized to determine the shapes of molecules based on electron pair repulsion.
  • Bond angles are measured between two terminal atoms and the central atom within a molecule.
  • Molecules can exhibit various shapes:
    • Tetrahedral shape occurs with four pairs of bonding electrons.
    • Linear shape is formed with two covalent single bonds without lone pairs.
    • Trigonal pyramidal shape has three single covalent bonds and one lone pair.

Hybridization

  • Hybridization refers to the formation of new orbitals from combined valence electrons.
  • Hybrid orbitals generated are identical to one another, such as in carbon.
  • Carbon commonly undergoes hybridization, forming sp3 orbitals when combining three p orbitals with one s orbital.
  • Methane (CH4) is an example of a molecule displaying sp3 hybridization.

Electronegativity

  • Electronegativity measures an atom's ability to attract electrons in a bond.
  • Fluorine holds the highest electronegativity value at 3.98 among all elements, classified under halogens in group 7A.
  • Francium has the lowest electronegativity at 0.7, belonging to alkali metals in group 1A.
  • Electronegativity decreases down a group and increases across a period.

Bond Types and Properties

  • The difference in electronegativities indicates bond type: a difference of 1.7 or more typically indicates an ionic bond.
  • Polar covalent bonds result from unequal electron sharing between bonded atoms.
  • A nonpolar covalent bond involves equal electron sharing between atoms.
  • The delta symbol (δ) indicates the less electronegative atom in a polar covalent bond.

Molecular Polarity

  • Molecules with only polar covalent bonds may or may not exhibit overall polarity based on their geometric arrangement.
  • Water (H2O) is considered a polar molecule with polar covalent bonds and unique geometry (bent).
  • Carbon tetrachloride (CCl4) is nonpolar overall, despite containing polar covalent bonds.
  • Ammonia (NH3) is polar because significant electronegativity differences result in a trigonal pyramidal shape.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Description

Test your understanding of key concepts from Chemistry Chapter 9 with these flashcards. Each card explores important definitions and statements regarding molecular structures and bonding. Perfect for quick review and reinforcement of your chemistry knowledge!

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser