CHAPTER 2 & 3

Question 1

• center of the second row of elements
• neither readily gives up nor readily accepts electrons but shares electrons
• occurs in a number of allotropic forms
• nonmetallic and tetravalent

Answer 1

carbon

Question 2

pure form of carbon

Answer 2

coal and soot

Question 3

• One of the most important compounds of carbon
• formed when carbon is heated in the absence of air

Answer 3

charcoal

Question 4

nothing but forms of an element with varying physical as well as chemical properties

Answer 4

allotropes

Question 5

2 allotropes of carbon

Answer 5

diamond
graphite

Question 6

• highly transparent
• one of the hardest substances known to man
• has a very low electric conductivity

Answer 6

diamond

Question 7

• opaque and black
• soft and often used as the “lead” in lead pencils
• very good conductor

Answer 7

graphite

Question 8

• Atoms lose, gain, or share electrons in order to have a full valence shell of eight electrons
• the understanding that most atoms seek to gain stability in their outer most energy level by filling the s and p orbitals of the highest energy level with eight electrons.

Answer 8

OCTET RULE

Question 9

electronic configuration of carbon

Answer 9

1s2 2s2 2p2

Question 10

Carbon is unique among the elements in the almost infinite capacity of its atoms to bond to each other in long chains, a process called __________ (Latin catena, chain)

• reflects the strength of the bond between adjacent carbon atoms in the molecule, both in relationship to similar bonds involving other elements of the carbon family and in relationship to bonds between carbon atoms and atoms of many other elements

Answer 10

catenation

Latin: catena, chain

Question 11

Only the ____, ____, ____, are stronger than the carbon-carbon single bond (C – C), and each of these is weaker than the carbon-carbon multiple bonds.

Catenation, via single or multiple bonds or both, combined with several other factors allows carbon to form more compounds than any other element. These factors are:

o The stability of certain carbon bonds, in particular of the C – H bond
o The existence of carbon in both sp2 and sp3 hybridizations
o The ability of carbon to form both chain and cyclic compounds
o The capability of many carbon compounds to exist in isomeric

Answer 11

C-H, C-F, C-O

Question 12

• idea that atomic orbitals fuse to form newly hybridized orbitals, which in turn, influences molecular geometry and bonding properties
• an expansion of the valence bond theory

Answer 12

hybridization

Question 13

shows the chemical composition of a substance; represents the elements present as well as the ratio in which the atoms of the element occur

Answer 13

chemical formula

Question 14

types of chemical formula1

Answer 14

1. Empirical Formula
2. Molecular Formula
3. Structural Formula
4. Molecular models

Question 15

shows the ratio of atoms in a compound

Answer 15

empirical formula

Question 16

shows the actual number of atoms in a compound

Answer 16

molecular formula

Question 17

shows the actual number and the order in which atoms are connected in a compound

Answer 17

structural formula

Question 18

• shows the shapes and relative sizes of molecules; shows the bonding sequence and geometrical arrangements of the atoms in a molecule (ball-and-stick & space-filling)
• Shows how the various atoms are bonded, and is more useful than only writing the molecular formula for a compound

Answer 18

molecular models

Question 19

____________ and ____________ of atoms in a molecule are extremely important because they
determine the properties of compounds

Answer 19

Bonding sequence and geometric arrangements

Question 20

Shows all the bonds in the molecules as individual lines with each atom written at the end of each line using its elemental abbreviation from the periodic table

Answer 20

displayed formula

Question 21

• Simplified form of displayed formula to prevent taking up too much space
• ____________: provides a very clear picture of where each of the atoms is bonded in space
• ____________: contains more information about bonding order than the molecular formula

Answer 21

CONDENSED FORMULA
- Partially condensed structure
- Fully condensed structure

Question 22

• All the hydrogen atoms are not shown and all the carbons are not labeled but rather are indicated at the end or bend in every line, leaving just a carbon skeleton with functional groups attached to it
• Any __________ (any other atom than carbon or hydrogen) and hydrogens attached to heteroatoms are shown in condensed form.
• following assumptions:
  o There is a carbon atom at each line junction and at the end of each line
  o There is enough hydrogen atoms attached to each carbon to make the total number of bonds on that carbon equal to 4.
  o All heteroatoms (and hydrogens attached to heteroatoms) are shown in condensed format on the skeletal
  structure.

Answer 22

• heteroatoms

LINE OR SKELETAL FORMULA

Question 23

Allows the visualization of the precise 3-D arrangement in parts of some molecules

Answer 23

wedge-dash formula

Question 24

Molecules that are mirror images of each other, but are not superimposable are defined as a special type of isomer called an ___________

Answer 24

enantiomer

Question 25

• Displays both the three-dimensional position of the atoms and the bonds between them
• Atoms are represented by spheres, connected by rods which represent the bonds; double and triple bonds are usually represented by two or three curved rods, respectively, or alternately by correctly positioned sticks for the sigma and pi bonds.
• Three different representations of CH4 on the left is the ball and stick model, in the center is the displayed formula, and to the right is the space-filling model.

Answer 25

ball and stick model

Question 26

• Atoms are shown as spheres whose diameters are proportional to their atomic radii
• The center-to-center distance between the spheres is proportional to the corresponding bond lengths

Answer 26

space filling model