Unit 2 + 3.1

Question 1

ability of atom to form a temporary or induced dipole

Answer 1

polarizability

Question 1

weak to strong van der waals forces + other two strong forces

Answer 1

LDF, Dipole-Dipole, Hydrogen (which is a type of D-D); ionic and metallic both similarly strong

Question 2

when are LDFs stronger?

Answer 2

1) when an atom or molecule has more total electrons (it is more polarizable) and
2) when the shape of the molecule is flatter/longer/thinner so there is more surface area

Question 3

when are hydrogen bonds strongest?

Answer 3

1) H-F, then H-O, then H-N b/c diff. in electronegativity (far apart on periodic table) and
2) when there are multiple sites for hydrogen bonding (which is not a bond but a force)

Question 4

when are ionic bonds strongest?

Answer 4

1) when charges are larger and
2) ions are smaller (both of which must be stated in answer), which is according to coulomb’s law

Question 5

when are metallic bonds strongest

Answer 5

1) smaller metallic cations and
2) more valence electrons

Question 6

what does the sum of superscripts of hybrid orbitals equal?

Answer 6

no. of electron clouds around central atom (no. of electron regions, not bonds)

Question 7

when is a molecule w/ a central atom nonpolar?

Answer 7

1) C and H only elements present
2) central atom has no lone pairs + all other atoms are identical

Question 8

2 electron regions + 2 bonding regions molecular geometry and bond angle

Answer 8

linear 180°

Question 9

3 electron regions + 3 bonding regions molecular geometry and bond angle

Answer 9

trigonal planar 120°

Question 10

3 electron regions + 2 bonding regions molecular geometry and bond angle

Answer 10

bent <120°

Question 11

4 electron regions + 4 bonding regions molecular geometry and bond angle

Answer 11

tetrahedral 109.5°

Question 12

4 electron regions + 3 bonding regions molecular geometry and bond angle

Answer 12

trigonal pyramidal <109.5°

Question 13

4 electron regions + 2 bonding regions molecular geometry and bond angle

Answer 13

bent <109.5°

Question 14

5 electron regions + 5 bonding regions molecular geometry and bond angle

Answer 14

trigonal bipyramidal 90°, 120°

Question 15

5 electron regions + 4 bonding regions molecular geometry and bond angle

Answer 15

seesaw <90°, 120°, 180°

Question 16

5 electron regions + 3 bonding regions molecular geometry and bond angle

Answer 16

T-shaped <90°, 180°

Question 17

5 electron regions + 2 bonding regions molecular geometry and bond angle

Answer 17

linear 180°

Question 18

6 electron regions + 6 bonding regions molecular geometry and bond angle

Answer 18

octahedral 90°

Question 19

6 electron regions + 5 bonding regions molecular geometry and bond angle

Answer 19

square pyramidal 90°, 180°

Question 20

6 electron regions + 4 bonding regions molecular geometry and bond angle

Answer 20

square planar 90°, 180°

Question 21

6 electron regions + 3 bonding regions molecular geometry and bond angle

Answer 21

T-shaped 90°, 180°

Question 22

6 electron regions + 2 bonding regions molecular geometry and bond angle

Answer 22

linear 180°

Question 23

what are the exceptions to the octet rule?

Answer 23

1) H only needs 1 pair
2) Be only needs 2 pairs
3) B and Al only need 3 pairs
4) NM in period 3+ b/c d orbitals

Question 24

what type of bonds can central atom halogens form?

Answer 24

only single bonds

Question 25

what formal charge is the most valid structure?

Answer 25

1) FC as close to zero, as many zeroes
2) negative formal charges on most electronegative atom

Question 26

interstitial vs substitutional alloy

Answer 26

inter alloy when small atoms are added into existing space btw metal atoms, sub alloy when added atoms replace metal atoms b/c similar size

Question 27

what is lattice energy?

Answer 27

energy to separate ions or bring together in only ionic compounds based on modification of coulomb’s law

Question 28

when do covalent bonds occur graphically?

Answer 28

lowest energy state = lowest point in the graph b/c attraction between nuclei is greatest but the repulsions are the least

Question 29

metallic character periodic trend

Answer 29

lower left corner have lowest ionization energies (lose electrons easily) so very reactive and most metallic