2.4 & 2.5 chem quiz

Question 1

lone-pair

Answer 1

a non-bonding pair of electrons, referred to as E in “AX” notation

Question 2

electron dot diagram (Lewis Structure)

Answer 2

a notation system that uses each element symbol to represent the nucleus (and inner electrons) and surrounds them with dots representing the valence electrons (used for individual atoms and molecules)

Question 3

making Lewis structures of Molecules

Answer 3

1. Determine total # of val. electrons
2. construct a skeleton
3. solve for lone-pairs
4. see what u need to get full octets
5. see if the available lone pairs align w what u need for octets
6. check the total # of val. electrons

Question 4

molecule skeleton

Answer 4

1. atom with lower group # (also corresponds to lower electronegativity) will be the central atom
2. hydrogen atoms only form one bond
3. halogens usually only form one bond (exceptions= if it’s a central atom , it can bond to other halogens or oxygen)
4. (a) oxygen forms 2 bonds & (usually) never bonds with itself (b) nitrogen forms 3 bonds (c) carbon forms 4
5. don’t make rings

Question 5

multiple bonds

Answer 5

covalent bonds that share more than one electron (only up to 3 bonds)

Question 6

expanded octets

Answer 6

more available electrons than needed :00000😎🤯👺

Question 7

polyatomic ion

Answer 7

non-metal atoms bonded covalently to each other with a nonzero net charge

Question 8

resonance

Answer 8

lewis structures w a double bond next to a single bond often have multiple correct lewis structures

Question 9

vsepr

Answer 9

Valence Shell Electron Pair Repulsion theory: groups of electrons will position themselves as far away from each other as possible while staying attached to the central atom

Question 10

AX2

Answer 10

bond angle: 180°
molecular shape: linear

Question 11

AX3

Answer 11

bond angle: 120°
molecular shape: trigonal planar

Question 12

AX2E

Answer 12

bond angle: 120°
molecular shape: bent or angular

Question 13

AX4

Answer 13

bond angle: 109.5°
molecular shape: tetrahedral

Question 14

AX3E

Answer 14

bond angle: 107°
molecular shape: triangle pyramidal

Question 15

AX2E2

Answer 15

bond angle: 104.5°
molecular shape: bent or angular

Question 16

AX5

Answer 16

bond angle: 120°, 90°
molecular shape: trigonal bipyramidal

Question 17

AX4E

Answer 17

bond angle: 120°, 90°
molecular shape: seesaw

Question 18

AX3E2

Answer 18

bond angle: 120°, 90°
molecular shape: T-Shaped

Question 19

AX2E3

Answer 19

bond angle: 180°
molecular shape: linear

Question 20

AX6

Answer 20

bond angle: 90°
molecular shape: octahedral

Question 21

AX5E

Answer 21

bond angle: 90°
molecular shape: square pyramidal

Question 22

AX4E2

Answer 22

bond angle: 90°
molecular shape: square planar

Question 23

Predicting Molecular Shape w Molecular formula

Answer 23

1. determine lewis structure
2. consider central atom: how many bonding pairs & how many lone pairs
3. assign an AXmEn notation to the molecule/polyatomic ion
4. refer to the appropriate electron group arrangement category

Question 24

bond dipole

Answer 24

partial charge assigned to bonded atoms due to differences in electron density, caused by electronegativity, inductive effects, etc

Question 25

molecular polarity

Answer 25

more than 2 atoms= molecular shape and bond polarity determine if the molecule is polar

Question 26

Guidelines for determining if a molecule is polar or non-polar

Answer 26

1. identical peripheral atoms & symmetrically arranged = cancel out bond dipoles
2. asymmetric molecule = polar molecule

Question 27

inTERmolecular force

Answer 27

attraction forces between molecules and ions and molecules

Question 28

inTRAmolecular force

Answer 28

chemical bonds within molecules

Question 29

dipole-dipole forces

Answer 29

with substances containing polar molecules, they will orient themselves so that oppositely charged dipoles will attract one another; results in high melting/boiling pts bc of the energy needed to overcome those attractions

Question 30

Hydrogen bonds

Answer 30

H-N, H-O, and H-F bonds are very polar due to large change in EN, leaving a large partial positive charge on the H end (bald hydrogen) and a large partial negative charge on the other end. This allows bald hydrogen to get very close with lone-pairs on other molecules, effectively giving hydrogen a wig

Question 31

London Dispersion forces

Answer 31

non-polar molecules are able to form an instantaneous dipole at any time, forming a chain reaction (“dispersion”) of instantaneous dipoles throughout the substance.

Question 32

ion-dipole forces

Answer 32

when ionic crystal lattices come into contact with the partially polar molecule water, they will break apart due to attraction to water’s dipole forces