Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > Lewis Theory > Flashcards

Lewis Theory Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

Lewis theory

A

Valence e- are responsible for chemical bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

According to Lewis theory how does a chemical bond form?

A

the outer most part of an atom will collide first ( where valence e- are located). Electrons will interact and form chemical bonds and structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Valence e-

A

electrons in the outer most shell of an atom, or e- with the highest “n” value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Covalent bond

A

When two atoms share electrons they form a covalent bond. The atoms overlap , the e- are located at the site of merger.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Ionic bond

A

When an e- is transferred from one atom to another, this causes each atom to have an opposite charge and to be attracted to each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Do atoms overlap in ionic bonds?

A

No, the ions sit side by side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Each dot in a Lewis structure represents what?

A

a valence e-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How many valence e- do noble gases tend to have?

A

All noble gases have 8 valence e-, except for Helium which has 2 valence e-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you determine the number of valence e- for an atom?

A

Elements in A columns have the same number of e- as their corresponding column number.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

If a nonmetal has no dots then it has no _____________.

A

brackets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ionic compound

A

metal bonded with a non metal, made up of anions and cations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When drawing the Lewis structure for an ionic compound what is important to remember?

A

The e- is transferred from the metal to the nonmetal. The metal becomes a cation and must have its positive charge written next to it. The anion is written in brackets with its charge written outside the brackets in the upper right-hand corner.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Covalent bonds are found in __________ compounds.

A

molecular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In molecular compounds a bonding pair can be written as a _____.

A

line

ex. H-O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are non bonding pairs called?

A

lone pairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Octet rule

A

most atoms prefer to have 8 e- in their valence shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Duet rule

A

Helium and Hydrogen prefer to have 2 e- in their valance shell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Are single bonds present in ionic compounds?

A

No, unless the single bond is part of a polyatomic ion that is part of the compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the rules for drawing the Lewis structure of a molecular compound?

A

1) Draw the skeletal structure
- The most metallic element in the middle
- symmetry
- “H” is never in the center, because it can only have 2 Valence e-
- Halogens are terminal
- Oxyacids; the acidic “H” must be next to “O”.
2) use periodic table to add up valence e-
3) Distribute valence e-
- begin by forming single bonds to connect atoms
- distribute remaining atoms to distal elements as lone pairs to satisfy octet
- distribute any left over e- to central atom as lone pair.
- elements after period 2 may have more than 8 e-
- Make double bonds if elements lack octet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When a molecular compound or polyatomic ion has a charge what must be written in its Lewis structure?

A

Poly atomic ions must be treated like molecular compounds. Molecular compounds and poly atomic ions must have their net charge written outside brackets in the upper left hand corner.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What kind of compound is SF sub6

A

It is a molecular compound so covalent bonds must be shown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do you determine formal charge?

A

subtract the number of lines and dots next to the atom from the number of valance e-. Each line and dot counts as one.

ex. Carbon has 5 valence e- but has 6 lines and dots, its formal charge in this case is -1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Polar

A

has charges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Nonpolar

A

Does not have charges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

If the formal charge of a molecule is zero what can be said about its stability?

A

It is very stable, likewise the more charges a molecule has the more unstable it is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How do you determine the charge of a molecule?

A

Add up all the formal charges of each atom in the molecule and the sum will give you the molecule’s overall charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What kind of compound is NaOH?

A

an ionic compound (poly atomic with metal)

28
Q

When drawing a lewis structure poly atomic ions must contain?

A

brackets and a charge

29
Q

When oil and water are mixed together oil tends to form a layer on top while water sinks to the bottom what can be determined from this observation?

A

Water is denser than oil.

30
Q

Describe a polar molecule.

A

A molecule that has an over all charge of zero but it is arranged in a way that has end as positive and the other as negative.

31
Q

Dipole moment

A

A dipole moment is a quantity that describes two opposite charges separated by a distance

32
Q

When a molecule is polar what will happen if its introduced to other polar molecules?

A

the molecules will attract; opposite ends will attract

33
Q

“Like dissolves like”

A

Polar substances will dissolve polar substances but not nonpolar and vice versa for nonpolar substances

34
Q

Will a polar substance mix with an ionic compound?

A

Yes, because they both have charges.

35
Q

Dipole

A

two poles of differing charges which are separated

36
Q

If both ends of a molecule are negative and the middle is positive is the molecule polar?

A

No

37
Q

How can molecular polarity (How polar a molecule is) be determined?

A

1) Draw Lewis structure
2) Identify bond polarity; the difference in electronegativity(look at chart and subtract larger from smaller.)
3) Look at line graph to determine polarity; 0-0.4 nonpolar, 0.4-2.0 polar, >2.0 Ionic.

38
Q

When looking at the periodic table what is the trend in electronegativity?

A

Electronegativity increases diagonally toward fluorine. (Fluorine is the most electronegative)

39
Q

A triangle next to EN means?

A

Difference in electronegativity; which means smaller electronegativity subtracted from the larger one.

40
Q

What is the range of electronegative difference for a nonpolar covalent bond?

A

0-0.4

41
Q

What is the range of electronegative difference for a polar covalent bond?

A

0.4-2.0

42
Q

What is the range of electronegative difference for an ionic bond?

A

> 2.0

43
Q

In the polar molecule H2O where do the e- spend most of their time?

A

Near oxygen because oxygen has a higher electronegativity, but hydrogen still has a pull because it has a decent amount of electronegativity.

44
Q

The “H’s” in H2O feel more positive so a _______ symbol can be written next to them.

A

sigma +

45
Q

The “O” in H2O feels more negative so a ________ symbol can be written next to it.

A

sigma -

46
Q

A sigma + or - symbol means what?

A

partial positivity or partial negativity.

47
Q

If the bond in a molecule is polar covalent does it have a dipole?

A

yes

48
Q

Is methane CH4 a polar or nonpolar molecule?

A

nonpolar, it has a small dipole moment but it is too small to be considered polar even though its electronegative difference is 0.4

49
Q

C-H bonds are _______.

A

Nonpolar

50
Q

O-H bonds are

A

polar

51
Q

The sum of all bond polarities determines what?

A

the polarity of a molecule

52
Q

The difference in electromag. of NaCl is 2.1 what bond does it have?

A

an Ionic bond

53
Q

The electromagnetic value of AlCl3 is 1.5 what kind of compound is it?

A

it is a molecular compound; even though it is a metal and a nonmetal the overall electromagnetic value puts it in the range of a polar molecule.

54
Q

When showing a dipole moment how is a dipole arrow drawn?

A

the part of the arrow with the vertical line indicates the positive end and the arrow indicates the negative end.

55
Q

When H2O’s Lewis structure is drawn its shape indicates that it is nonpolar, but the molecule is polar, what happened?

A

The shape of H2O is drawn incorrectly. The shape of H2O is bent.

56
Q

When making sure a molecule has the right shape what must be checked?

A

polarity must be checked first , then molecule must be drawn corrected to show polarity if need be.

57
Q

How can stability of a molecule be determined?

A

the less charges the more stable and when no charges are present on central atom it is more stable.

58
Q

How do you check to see if a molecule’s shape is polar?

A

1) The molecule has net movement
2) Draw an e- map
3) Draw dipole arrows; draw arrows toward most electronegative element. if arrows run into each other they cancel out, if they run at an angle to each other they create a resultant vector (the shape is polar.).

59
Q

VSEPR Theory

A

Valence shell electron pair repulsion

60
Q

Why is VSEPR theory important?

A

they help us to draw molecules with the right shape

61
Q

Why do molecules have certain shapes?

A

valence e- pairs are repelled from each other , e- are placed in a certain way to minimize repulsion.

62
Q

Electron geometry

A

electron shape is determined by e- groups

63
Q

What is an e- group?

A

a single, double, or triple bond, and lone pairs are all e- groups

64
Q

Solid lines are _______.

A

on wall

65
Q

Wedges are ________.

A

protruding out of the wall

66
Q

Dashed lines are _______.

A

behind or in the wall

67
Q

Each line, wedge, and dash represents what?

A

a single bond

Chemistry (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions