Gc(3) Bonding And Chemical Interactions

Front 1

Can you tell what the physical and chemical properties of a compound are by looking at the individual elements?

Back 1

No, combining elements creates a whole new set of properties in the molecule.

Front 2

What does the octet rule have to do with bonding?

Back 2

Atoms will bond to fulfill their octet of electrons in the outermost shell.

Front 3

Do all elements follow the octet rule?

Back 3

No. Hydrogen can only have two valence electrons. Lithium will bond to get two. Beryllium will bond to four. Boron will bond to six. Any elements beyond the second row can have more than eight valence electrons by incorporating them into d orbitals.

Front 4

Two atoms bond by one giving its electron to the one with more electron affinity. What kind of bond is this?

Back 4

ionic bond

Front 5

Two atoms bond by sharing an electron pair. What kind of bond is this?

Back 5

covalent bond

Front 6

What is the name of a bond that is partially covalent and partially ionic?

Back 6

polar covalent bond

Front 7

What is a cation?

Back 7

an atom that looses an electron and has a positive charge

Front 8

What is an anion?

Back 8

an atom that gains an electron and has a negative charge

Front 9

What must be true of the atoms forming an ionic bond?

Back 9

one must have a lower ionization energy and one must have a greater electron affinity. the difference in electronegativity must be greater than 1.7

Front 10

What is another name for an ionic bond?

Back 10

electrovalent bond

Front 11

What are the general physical properties of an ionic compound?

Back 11

high melting point and boiling point
can conduct electricity in liquid/aqueous states
solids form crystal lattices

Front 12

What kind of electronegativity relationship produces covalent bonds?

Back 12

the atoms must have similar electronegativities

Front 13

What are the general physical properties of a covalent compound?

Back 13

low melting point
do not conduct electricity

Front 14

What is bond order?

Back 14

the number of shared electron pairs between two atoms.
single bond = 1
double bond = 2
triple bond = 3

Front 15

What are the two features of a covalent bond?

Back 15

bond length - average distance between the two bonded nuclei

bond energy - energy required to separate two bonded atoms

Front 16

In a Lewis structure, what do the dots represent? The lines?

Back 16

dots - nonbonding/valence electrons

lines - a pair of shared electrons

Front 17

When writing a Lewis structure, what atom goes in the middle?

Back 17

the least electronegative atom

Front 18

What is the formula for the formal charge of an atom?

Back 18

formal charge = V - 0.5N_bonding - N_nonbonding

V=# of valence electrons in the free atom

Front 19

What is resonance?

Back 19

The ability of a molecule to have more than one Lewis structure.

Front 20

If there is resonance, which structures are more stable and therefore preferred?

Back 20

-no formal charges, or small, are preferred to larger charges
-negative charge on the most electronegative atom

Front 21

What conditions make a covalent bond polar?

Back 21

difference in electronegativity between o.4 and 1.7

Front 22

What types of molecules have nonpolar bonds?

Back 22

diatomic molecules, hydrogen, oxygen, chlorine, nitrogen

Nonpolar covalent bonding occurs between atoms that have the same EN.

Front 23

What is a coordinate covalent bond?

Back 23

a covalent bond between two existing covalent molecules, often occurs with Lewis acid-base compounds

Front 24

How many regions of electron density does a linear molecular geometry have? What angle does it form?

Back 24

2, 180'

Ex. AX2

Front 25

A molecule has 3 regions of electron density. What is it's molecular geometry? Angle btw pairs?

Back 25

trigonal planar, 120'

ex. BH3

Front 26

How many regions of electron density does trigonal bipyramidal have? Angles?

Back 26

5

90', 120', 180'

Front 27

CH4 would have what kind of molecular geometry?

Back 27

4 regions of electron density = tetrahedral 109.05 degrees

Front 28

A molecule has 6 regions of electron density, what is the molecular geometry?

Back 28

octahedral

Front 29

Will a molecule with polar covalent bonds always be polar?

Back 29

No, the bond dipole moments may cancel each other out, making a nonpolar molecule.

Front 30

What is the shape of the s orbital?

Back 30

sphere

Front 31

How many orbitals does p have?

Back 31

three, px, py, pz

dumbbell shaped, at right angles

Front 32

What is a molecular orbital?

Back 32

the interacting orbitals of a molecule
The orbitals of covalent bonds overlap, forming a bonding orbital or antibonding orbital.

Front 33

What is the name of head-to-head orbital overlap?

Back 33

sigma bond

Front 34

When does a pi bond form?

Back 34

when overlapping orbitals are parallel

Front 35

What are intermolecular forces?

Back 35

attractive forces and interaction between molecules

Front 36

What are dipole-dipole interactions? What phases are they commonly present and why? Affects on bp?

Back 36

interactions between polar molecules so that the positive end of one is close to the negative end of another

Present in solid and liquid phases but not often in gas bc molecules are further apart.

Polar species have higher bp than nonpolar.

Front 37

To what atoms does hydrogen bond during hydrogen bonding?

Back 37

electronegative atoms such as O, F, N

Front 38

Does size play a part in dispersion forces?

Back 38

Yes, large molecules have electrons further from the nucleus and can for temporary dipoles more easily

Front 39

What interactions are considered van der Waals forces?

Back 39

dipole-dipole and dispersion

Front 40

Which intermolecular force is the strongest? Weakest?

Back 40

strongest - hydrogen bonding
weakest - dispersion forces

Front 41

What is VSEPR theory?

Back 41

Valence Shell Electron Pair Repulsion Theory.

theory uses Lewis structures to predict the molecular geometry of covalently bonded molecules.

States that 3D arrangment of atoms surrounding a central atom is determined by the replusions btw the bonding and nonbonding electron pairs in the valence shell of the central atom.

These electrons pair arrange themselves as far apart as possible - minimizing replusion.

Front 42

What are the 3 steps of VSEPR Theory?

Back 42

1. draw lewis structure of molecule.
2. Count total # of bonding and nonbonding electron pairs in valence shell of central atom.

3. Arrange the electron pairs around the central atom as far apart as possible.

Front 43

In describing the shape of a molecule, only the arrangments of what is considered?

Back 43

atoms

Front 44

Quantum #s Review

Back 44

1. For any value of n, there are n values of L (0-->n-1).

2. L=0 (s), L=1(p), L=2(d)

3. for any value of L, there are 2L+1 values of mL (#of orbitals); values themselves will range from -L to L.

Front 45

What is Hydrogen bonding? And affects on bp?

Back 45

specific, unusally strong form of dipole dipole interaction.

increases bp bc energy required to break h bonding.

Front 46

What are dispersion forces and their signficance?

Back 46

weak, compared to intermolecular forces, short lived btw molecules that are close toegether.

keeps substance together as solid or liquid.
Determine whether two substances are miscible or immiscible in solution phase.

Front 47

What is order of increasing bp of the following forces:

Van Der Waals, Dipole/Dipole, H Bonding, Ionic?

Back 47

Van Der, Dipole/dipole, Hbonding, Ionic

Front 48

Periods that can exceed its number of valence electrons of 8

Back 48

3+

Front 49

What causes a molecule to be drawn into a magnetic field?

Back 49

If they are paramagnetic and any compound with an odd # of valence electrons is paramagnetic.