Chapter 6- Covalent Bonding Flashcards Preview

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Flashcards in Chapter 6- Covalent Bonding Deck (39):
1

What sort of electronegativity do non-metalliac elements have?

Generally high

2

How do non-metalliac elements get a full shell of electrons when reacting with another non-metalliac element?

Share electrons

3

What does the sharing of electron pairs produce?

A covalent bond

4

What are non-bonding elecrtrons referred to in reagrds to electron dot diagrams?

Lone pairs

5

How do you draw electron dot diagrams?

All inner shell electrons are replaced by elements symbol and the outer shell electrons are represented by dots.

6

Rules for Drawing Electron Dot Diagrams

1. Draw the dot diagrams for each of the atoms in the molecule.
2. Unpaired electrons are avaliable for sharing to form a covalent bond.
3. Paired (lone pairs) do not participate in the bonding.
4. The atom with the most bonding electrons is placed in the centre, with other atoms bonded to it.

7

What simple is used to represent a shared pair?

-

8

How many maximum bonds can it have?

Three

9

Name the five common shapes of common molecules

-Tetrahedral
-Pyramidal
-V-Shaped
-Linear
-Planar

10

Steps in naming a non-metalliac molecule

1. The first element in the formula is named in full
2. The second element is named as if it is an anion and is given an -ide suffix
3. The number of each type of atom in the molecule is indicated by a prefix

11

Define non-polar covalent bonds

Bonding electron pairs is shared equally and is distributed evenly between the two nuclei.

12

In which elements does non-polar covalent bonds exist?

-The same elements
-Elements with the same electronegativity

13

When do polar covalent bonds occur?

When the bonding of electrons are unequally shared

14

Explain polar covalent bonding

The elements will have different electronegatives. The shared electrons will move closer towards the element with higher electronegativity, thus creating a negative charge on this side of the molecule. Therefore the other side becomes slightly postively charged.

15

What is the charge seperation of polar covalent bonding also known as?

Dipole-dipole

16

Is a polar covalent bond ever truely covalent?

NO

17

What happens when there is a greater difference of 2.0 in the molecules electronegatives?

An ionic bond forms

18

What determines a polar molecule?

One end is slightly positive and the other is slightly negative.

19

What are the rules for determining polarity?

1. Draw an electron dot diagram of the model
2. Apply the vespr rules to draw the shape of the diagram
3. Use electronegatives to determine bond dipoles
4. Use the shape to determine whether bond dipoles cancel out

20

Define intramolecular bonding?

Bonding within molecules

21

Define intermolecular bonding?

Bonding between molecules

22

Define intermolecular force

The force of attraction between molecuels

23

Explain the relationship betwen moleculer force and the boiling point?

The stronger the molecular force the higher the boiling point.

24

What are the three types of intermolecular bonding?

Dipole-Dipole
-Dispersion
-Hydrogen Bonding

25

Explain dispersion forces

-Occur when nuclei attract electrons from neighbouring atoms attract electrons
-At any point in time the electrons can be found on either side of the moelcule.
-All molecules have dispersion forces

26

Explain dipole-dipole interactions

-The positve side of a molecule attracts a negative side of another molecule
-Have dispersion forces aswell

27

What is hydrogen bonding a special case of?

Dipole-dipole interactions

28

Explain hydrogen bonds

When hydrogen bonds to FON the electrons move slightly towards that atom leaving hydrogen exposed.
-Hence another dipole can come alot closer to the hydrogen and have alot stronger bond

29

What are the strongest type of bonds?

Hydrogen

30

What is the overall charge on a covalent molecule?

0

31

Define non-polar covalent bonds

Formed between atoms with the same electronegavitiy or they are the same element.

32

Define polar covalent bonds

Electrons are unequally shared
-Elements have different electronegatives

33

What are non-polar molecules?

Only non-polar bonds

34

What defines a polar molecule?

One end is slightly negative and the other is slightly postive.

35

What sort of bonding occurs in all forms of water?

Hydrogen

36

Explain the unusualness of waters properties

-It expands upon freezing.
-It has a very high melting point compared with other substances

37

Why does ice float in water?

The open hexagonal crystalline lattice move the water molecules furthur apart than the liquid state, because water expands on freezing this means it has a lower density in the solid form, hence the ablity to float.

38

What is a discrete molecule?

A covalent molecule in which the intermolecular forces are really weak

39

What physical properties do intermolecular substances have?

-low melting point and boiling point due to weak intramolecular forces
-liquid or gaseous at room temp
-do not conduct electrcity