Chapter 6 Chemical Bonds

Question 1

Chemical Bond

Answer 1

A force of attraction of the nuclei of one atom for the valence electrons of another atom

Question 2

Why do atoms want to chemically bond?

Answer 2

Lowers energy of separate atoms

Question 3

What are the types of chemical bonding?

Answer 3

Ionic, covalent, and metallic

Question 4

What is the composition for ionic bonds?

Answer 4

Non-metal + metal

Question 5

What is the composition for covalent bonds?

Answer 5

Non-metal + non-metal

Question 6

What is the composition for metallic bonds?

Answer 6

Metal + metal

Question 7

What is electron behavior in ionic bonds?

Answer 7

Electro transfer from metal to non-metal

Question 8

What is electron behavior in covalent bonds?

Answer 8

Sharing electrons between non-metals

Question 9

What is it called when there is equal sharing in covalent bonds?

Answer 9

Nonpolar, covalent

Question 10

What is it called when there is unequal sharing in covalent bonds?

Answer 10

Polar, covalent

Question 11

What is electron behavior in metallic bonds?

Answer 11

Metal cations with delocated electrons

Question 12

Metallic bonds electron behavior is called what?

Answer 12

“Sea of electrons”

Question 13

Covalent bonds has a difference of what in electronegativity? What is its Covalent character and ionic character like?

Answer 13

Zero difference in electronegativity with high covalent character and low ionic character.

Question 14

Polar covalent bonds covalent character and ionic character are like what? What is the difference in their electronegativity?

Answer 14

Medium covalent character and medium ionic character with a intermediate difference in electronegativity.

Question 15

What is the difference of electronegativity in ionic bonds and what is its ionic and covalent character like?

Answer 15

Large difference in electronegativity with low covalent character and high ionic character

Question 16

What are the two “results” possible when chemical compounds form?

Answer 16

Molecules and formula units

Question 17

What is a molecule?

Answer 17

A group of neutral covalently bonded atoms. Smallest units of a covalent compound.

Question 18

What is a formula unit?

Answer 18

The simplest (smallest) part of an ionic compound.

Question 19

Bond energy

Answer 19

The energy required to break a chemical bond and form neutral isolated atoms

Question 20

Bond length

Answer 20

The average distance between two bonded atoms

Question 21

Diatomic molecules

Answer 21

some elements are found naturally in pairs

Question 22

Ionic Compounds

Answer 22

• Crystalline solids (made of ions), ions have very strong forces of attraction for each other, forces extend throughout crystal structure
• High melting point
• Conduct electricity when melted and when dissolved in water (nonconductors as solids)
• Soluble in water but not in nonpolar liquids
• Brittle and hard solids

Question 23

Covalent Compounds

Answer 23

• Gases, liquids, or solids (made of molecules)
• Low melting and boiling points
• Poor electrical conductors in all phases (Nonconductors when dissolved in water)
• Many are soluble in nonpolar liquids but not in water
• Atoms are held strongly to each other within molecules, but molecules do not have strong forces of attraction for each other
• Brittle and “soft” solids

Question 24

Ionic Solids

Answer 24

• Ionic solids are solids composed of ionic particles (ions)
• These ions are held together in a regular array by ionic bonding
• Ionic bonding results from attractive interactions from oppositly charged ions
• In a typical ionic solid, positively charged ions are surrounded by negatively charged ions and vice-versa
• The alternating of the positive and negative ios continues in three dimensions
• The regular repeating pattern is analogous to the tiles on a floor or brick wall
• Called the crystal lattice

Question 25

Ionic Compounds

Answer 25

• Crystalline solids (made of ions)
• High melting and boiling points
• Conduct electricity when melted or dissolved in water
• Electrolytes
• Many are soluble in water but not in non-polar liquid

Question 26

Metallic Compounds

Answer 26

• Solids
• Malleable (can be beaten into sheets) and ductile (can be pulled out into wires)
  ~ because of ability of the atoms to roll over each other in new positions without breaking metallic bond
• Range of melting points
• Excellent electrical conductors in all phases

Question 27

Metallic Bonds

Answer 27

• The properties of metals suggest that their atoms passes strong bonds
• ease of conduction of heat and electricity suggest that electrons can move freely in all directions in a metal
• General observations give rise to a picture of “positive ions in a sea of electrons” to describe metallic bonding

Question 28

Electron Sea Model

Answer 28

• Atoms in a metallic solid contribute their valence electrons to form a “sea” of electrons that surrounds metallic cations
• Delocalized electrons are not held together by any specific atom and can move easily throughout the solid
• A metallic bond is the attraction between these electrons and the metallic cation

Question 29

Covalent (Molecular) Compounds

Answer 29

• Gases, liquids, or solids (made of molecules)
• Low melting and boiling points
• Poor electrical conductors in all phases
• Many soluble in non-polar liquids but not in water

Question 30

Goal for Lewis Dot Structures

Answer 30

GOAL: Satisfy the octet for each element so it is at its lowest energy
however…
H if fine with 2 electrons
B is good with 5 electrons

Question 31

Lewis Dot Structures

Answer 31

• Center atom is one with lowest number of valence electrons (lowest electronegativity value)
• Hydrogen will always form a single bond
• Polyatomic ions:
  ~ add/remove electrons from center element or strongest electrons
• If formula contains more than one oxygen, do one oxygen at a time

Question 32

Coordinate covalent bond

Answer 32

Electrons came from one element