Test 6- Bonding Flashcards Preview

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Flashcards in Test 6- Bonding Deck (35):
1

Why do bonds form?

Energy! Atoms strive to be at lowest energy possible

2

Diagram that shows relationship between potential energy level and distance between atoms

Be able to draw

3

Chemical bond

Mutual electrical attraction between nuclei and valence (outer) electrons of different atoms. This binds the atoms together. All about valence electrons!

4

Model to show chemical bonding

Lewis dot diagram shows elemental symbol and bonding VE

5

Lewis Dot diagram basics

One dot per VE
--36
4???1
7???2
--58

6

Stable electron configuration

- Same as nobel gas
- Elements lose or gain electrons to have the same number of electrons as a nobel gas

7

Octet rule

- Elements strive for 8e- in outer energy level.
- some only need 2 e- to be stable like He
- Elements in part A of periodic table

8

Exceptions to octet rule

- H only needs 2 e-
- B needs 6 e-
- Be needs 4 e-

9

Electronegativity

Relative scale 0-4, the attraction an atom has for a pair of e- in a bond
- Increases up and right
- Electrons close to each other on periodic table share electron to meet the octet rule (covalent)

10

Share electrons

- Similar electronegativity
- same area of the periodic table
- share e- to fufil octet rule
- covalent bond

11

Transfer electrons

- Different electronegativity
- far apart on the periodic table
- Ionic bond

12

Nonpolar covalent bond

- Perfect sharing
- Same attraction
- same electronegativity
- Electronegativity difference Range: 0-.4

13

Polar covalent bond

- Unequal sharing
- Range: .4<_1.9

14

Ionic bond

- Not sharing
- Complete transfer
- Range: above 1.9

15

Drawing Ionic bonds

1. Draw lewis dot for both elements
2. transfer to make 8
3. Write both elements with brackets
4. Indicate the charge
- Might have to draw more than one to make 8

16

Characteristics of Ionic compounds

- Simplest piece is a Formula unit
- Crystal lattice AKA ionic latice
- Always solid at room temperature
- Soluble in water
- Conducts electricity
- High melting point

17

Formula Unit

Simplest ration of the ions

18

Crystal lattice AKA ionic latice

- Cluster of Na+ and Cl-
Na+Cl-Na+Cl-
Cl-Na+Cl-Na+
Na+Cl-Na+Cl-
- Not smooth

19

Ionic compounds solids at room temperature

So strongly attracted that it takes a lot of energy to separate

20

Ionic compounds soluble in water

Water has a great attraction to the compound and the high energy breaks them apart. (Brad Pitt and Angelina Jolie)
- NaCl(s) --> NaCl(aq)

21

Ionic compounds conducting electricity

- Solution of ions and liquid ionic compounds
- has to be s solution or melted/liquid
- Triangle of battery, light, and beaker with solution with wires going into the solution

22

Nomenclature

- Naming/writing formulas
- IUPAC- International Union of Pure and Applied Chemists

23

Naming Ionic compounds

- Binary
- Name metal first
- When writing a formula, the net charge for all compounds is zero
- Subscript indicates number of atoms/ions of the element it follows
- Criss cross- use charge as subscript of other element

24

Binary

- Ionic
- 2 elements
- Metal and nonmetal
- End in ide
- name nonmetal and change ending to ide

25

Naming transitional metals

Use roman numerals to indicate charge of metal ion

26

Tertiary Ionic compounds

- More than 2 elements
- cation(+)/anion(-)
- Don't end in ide
- All contain polyatomic ions

27

Naming representative metals

- more than 2 elements
- Name metal and name polyatomic ion
- Subscript doesn't matter
- Not all compounds that end in Ide are not binary but all binary compounds end in ide
- If you have more than one polyatomic ion, it must be in parenthesis

28

Transitional metals with polyatomic ions

Use roman numerals to indicate charge

29

Covalent bonds

- Occur between 2 nonmetals (in general)
- 2 types of covalent bonds based on electronegativity difference
- 0-.4= nonpolar covalent bond, equal sharing
- 0<_1.9= polar covalent bond unequal sharing
- Exist as individual molecules
- Molecule=smallest piece of covalently bonded particle

30

Smallest piece of covalent vs. Ionic

- Covalent= molecule
- Ionic= Formula unit

31

Representing e- sharing covalent bond with a lewis dot diagram

- Still all atoms strive for 8e-
- No transfer
- No charges or brackets
- Dots and circles
- Covalent bond is the overlap
- e- always shared in pairs
- Single if one pair is shared
- Double if two pairs are shared
- Triple if three

32

Line structure

Each line represents a pair of electrons

33

Lewis Dot for polyatomic ions

- have circles (2 nonmetals) and brackets (charge)
- Lower electronegativity goes in the middle
- Add/subtract electrons according to charge

34

Coordinate covalent/Dative bonds

Both shared electrons are from one element

35

Lewis Dot and Line are both

structural diagrams