Test 6- Bonding Flashcards
Why do bonds form?
Energy! Atoms strive to be at lowest energy possible
Diagram that shows relationship between potential energy level and distance between atoms
Be able to draw
Chemical bond
Mutual electrical attraction between nuclei and valence (outer) electrons of different atoms. This binds the atoms together. All about valence electrons!
Model to show chemical bonding
Lewis dot diagram shows elemental symbol and bonding VE
Lewis Dot diagram basics
One dot per VE --36 4???1 7???2 --58
Stable electron configuration
- Same as nobel gas
- Elements lose or gain electrons to have the same number of electrons as a nobel gas
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
Exceptions to octet rule
- H only needs 2 e-
- B needs 6 e-
- Be needs 4 e-
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)
Share electrons
- Similar electronegativity
- same area of the periodic table
- share e- to fufil octet rule
- covalent bond
Transfer electrons
- Different electronegativity
- far apart on the periodic table
- Ionic bond
Nonpolar covalent bond
- Perfect sharing
- Same attraction
- same electronegativity
- Electronegativity difference Range: 0-.4
Polar covalent bond
- Unequal sharing
- Range: .4<_1.9
Ionic bond
- Not sharing
- Complete transfer
- Range: above 1.9
Drawing Ionic bonds
- Draw lewis dot for both elements
- transfer to make 8
- Write both elements with brackets
- Indicate the charge
- Might have to draw more than one to make 8