Chemical Bonds I Flashcards Preview

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Flashcards in Chemical Bonds I Deck (30):
1

Chemical Bonds

1. Attraction between atoms or ions
2. Are due to the attraction between the positive nucleus and the negative electrons

2

Potential Energy

Stored in bonds between atoms/ions

3

Chemical Energy

Energy involved in making/breaking bonds

4

Energy Changes in Bonds

1. When two atoms are bonded --> lower/stable potential energy level
2. When stronger bonds form --> Exothermic Reaction + Less potential energy

5

Relationship between stabiltilty and potential energy

Inverse

6

Exothermic vs Endothermic

Exothermic: Stability is high, potential energy is low when compared to reactants
Endothermic: Stability is low, potential energy is high when compared to reactants

7

Endothermic/Exothermic Diagram

Bottom is potential energy
Top is kinetic energy

8

Electronegativity

0-.3 --> NPC
.3-1.7 exclusive --> PC
>1.7 inclusive --> I

9

Ionic Bonds

Attraction between ions
Nonmetal and Metal

10

Lewis Structures for Ionic Bonds

Must have charges
May draw arrows, or have nonmetal have a full shell

11

Properties of Ionic Compounds

As solids don't conduct electricity
When melted/in aqueous solution conduct electricity
High melting points
Have crystalline lattice structure
Very strong

12

Covalant Bonds

Either equally/unequally shared electrons

13

NPC

Shared equally between two nonmetals
END is

14

PC

Shared unequally between two nonmetallic atoms
.3

15

Properties of Covalant Compounds

Low melting Point
Dull
Brittle
Nonconductive

16

Network Solid

Chemical compound where the atoms are bonded covalently in a continuous network
Entire network is considered a molecule

17

Properties of Network Solids

Very high melting point
Very strong covalent bonds
Very hard
Not soluble in water

18

Examples of Network Solids

Diamond --> C
Silicon Dioxide --> Si02
Graphite --> C in two dimensional layers

19

Coordinate Covalent Bonds

When both electrons from a bond are shared by only one of the two atoms

20

Metallic Bonds

Electrons in solid metals are free travel atom to atom
Metals became cations due to loss of electrons
Attraction between the mobile electrons and the metals cause a strong bond to form
Called Sea of Electrons

21

Properties of Metallic bonds

Luster
Ductile
Malleable
Conductor

22

Localized Electron Model

Electron Pairs are assumed to be localized on a particular atom or in the space between two atoms.
Description of valence electron arrangement (Lewis Structure)
VSEPR
Description of atomic orbital types used to share electrons or hold lone pairs

23

Lone Pair Electrons

Electrons located on an atom

24

Bonding Electrons

Electrons found in the space between the atoms

25

2nd Row Elements

C,N,O,F use octet rule
Often have fewer than eight electrons, they are very reactive

26

3rd Row and heavier elements

Can exceed the octet rule, using empty d valence orbitals

27

VSEPR

Valence Shell Electron Pair Repulsion

28

Intramolecular

Involved in bringing atoms together to a compound
Ionic
Polar Covalent
Nonpolar Covalent

29

Intermolecular

Involved in bringing molecules together
Dipole-Dipole - Strong, Unequal/Partial charges
Hydrogen Bonds (H to F,O,N) - Strongest
Weak/Van Dar Waal's - Weakest

30

Weak Intermolecular Forces

Small nonpolar molecules, best in liquid/solid phases with low temp and high pressure
Stronger when closer together
Smaller the molecule --> weak
Larger the molecule --> strong
Smaller nonpolar molecules, tend to be gases at room temperature, give them low boiling points --> Noble Gasses
Larger nonpolar molecules, tend to be liquids and solids at room temperature
Diatomic Molecules are also examples