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Victoria Robinson Inglés 41 fichas

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13 subatomic particlesprotons neutrons and electrons
2Mass number = ? Atomic number = ? Electrons = ?For a neutral atom, protons = electrons
3Electrons of an ion = ?
4Isotopes ? Atomic mass ?Isotopes: Atoms with same atomic number (number of protons) but different mass
number (number of neutrons)
Atomic Mass: weighted average mass of element’s naturally occurring isotopes
5Orbitals• A wave function, ψ, used to determine the volume of space around
nucleus that an electron is most likely to occupy.
• Atomic orbitals described by quantum numbers n, l, m
6s orbitalonly 1
7p orbitalsthere are 3
8d orbitalsthere are 5
9quantum numbers n, l, mn = energy level
l = shape
m = orientation
10Electron Configuration DiagramsOrganization of atomic orbitals in electron shells of increasing energy
shells (n=1, n=2, n=3, ...)
11SubshellsWithin a shell
For example:
Shell - n=2
Subshell - 2s, 2p
12valence electrons- Electrons in outermost shell
- participate in bonding
13Electron Configuration Aufbau Principle:lowest E orbitals fill-up first
(1s, 2s, 2p, 3s, 3p…)
14Electron Configuration Pauli Exclusion Principle:2 e- max in each atomic orbital and those
must have opposite spin
15Electron Configuration Hund’s rule:orbitals in a subshell must be singly occupied with same spin before doubly occupied (with opposite spin)
16Covalent- electron sharing
- nonmetal and nonmetal
17ionic- Forms ions
- gain or lose electrons
- metal and nonmetal
18Drawing Lewis structures streps1. Sum valence electrons of all atoms in molecule (1+4+5=10)
2. Place least electronegative atom in center (except for H) and connect all
atoms by single bonds
3. Fill octets of all atoms (except for H) with lone pairs of e4. Count ein the structure; if more than count in step 1 then create multiple bonds
19Non metals that we use in OrgoH, C, N , O, F, Cl, Br, I
maybe P & S
20Electronegativy Trend- Everything points to Fluorine
- O > N > C
21H in Lewis Structurescannot hold the center position
22Resonance structures for an ion OCN ^ -
23Carbon in its neutral stateHas 4 bonds
24Nitrogen in its neutral stateHas 3 bonds
and 1 lone pair
25Oxygen in its neutral stateHas 2 bonds
and 2 lone pairs
26X = F, Cl, Br, I in its neutral stateHas 1 bond
and 3 lone pairs
27Formal charge"every bond (line) counts as 1, every electron (dot) counts as 1!!"
= # of valence electrons - (each dot + each line)
28Gaining a bond is (+) Losing a bond is (-)Example:
Nitrogen in its neutral state has 3 bonds and one lone pair
Now it has 4 bonds so the charge is (+)
Why? - a lone pair is more negative than one bond
29Resonance structures and formal chargescalculate the formal charge for each atom in the resonance structures
30Best to Worst Resonance Structure The rules.The best resonance contributors have:
1. Maximum number of covalent bonds
2. Least charge separation
3. (-) charge on most electronegative atom and (+) charge on least electronegative atom
*Electronegativity - O > N > C
31sp3 hybrid orbitalsTetrahedral Geometry
32sp2 hybrid orbitalsTrigonal Planar Geometry
33sp hybrid orbitalsLinear geometry
34Sigma bonds• Head to head orbital overlap
• Cylindrical symmetry of electron density around internuclear axis
35Pi bonds• Side to side orbital overlap
• Electron density above and below internuclear axis
36Single vs double vs triple bondsSingle = 1 sigma bond
Double = 1 sigma and 1 pi bond
Triple = 1 sigma and 2 pi bonds
37Electron promotion- allowing carbon to have 4 hybrid orbitals ready to bond
- in between 2s and 2p energy levels
38sp3 vs sp2 vs sp- depending on number of domains C has, circle 2, 3, or 4 sp orbitals
39This carbon has 3 domainsso, circle 3 sp orbitals
40Predicting Hybridization- Electron domains = single b., double b., triple b., lone pair (both dots together count as 1)
1. Count electron domains around atom of interest
2. 1 electron domain = 1 site of electron density
4 domains = sp3
3 domains = sp2
2 domains = sp
41Predicting Hybridization when lone pairs are omitted in drawings- remember the octet rule. there should be a total of 8 electrons. add a lone pair if drawing has less than 8. then count it as a domain