Chapter 6 - Covalent Bonding

Question 1

what is covalent bonding

Answer 1

where 2 atoms share valence electrons in an attempt to satisfy the octet rule.

Question 2

what is a molecule

Answer 2

a group of atom.

Question 3

what are diatomic molecules

Answer 3

covalent bonded molecule between two of the same atom

Question 4

what are electron dot diagrams also called?

Answer 4

lewis diagrams

Question 5

paired electrons are also called…

Answer 5

lone pairs

Question 6

unpaired electrons can also be called…

Answer 6

bonding electrons

Question 7

what is the central atom?

Answer 7

the atom in a molecule that has the most bonding electrons. it is placed in the centre with the other atoms bonded to it.

Question 8

structural formulas can also be called…

Answer 8

valence diagrams or shape diagrams

Question 9

define ‘molecular’

Answer 9

relating to or consisting of molecules

Question 10

steps to naming covalent compounds

Answer 10

1. the first elements name is in full
2. the second element is named like an anion with the
   - ide suffix.
3. the number of atoms of each is given by a prefix
4. if a vowel is between the name and the suffix, it is dropped for better pronunciation

Question 11

what are non-polar bonds

Answer 11

where the shared electron pair is shared equally between the nuclei of 2 atoms in a uniform distribution.

Question 12

what are polar bonds

Answer 12

where the shared electron pair is un equally shared and thus is unsymmetrically distributed between the 2 atoms.

Question 13

steps to determine polarity

Answer 13

1. draw a shape diagram
2. use the electronegativities to determine poles [starting with the lowest electronegativity]
3. use shape and poles to see if molecule is polar. if dipoles don’t cancel or molecule is not symmetrical, it is polar.

Question 14

what are intermolecular forces

Answer 14

the attraction between molecules of a substance

Question 15

define dispersion forces

Answer 15

where the nucleus of a neighbouring atom is attracted to the negative instantaneous dipole of another atom. They are weak but accumulate with more electrons.

Question 16

what affects the strength of dispersion forces

Answer 16

more electrons=stronger

shape that allows molecules to come closer together=stronger

Question 17

define dipole-dipole attraction

Answer 17

if both molecules a polar, they have permanent dipoles which attract to opposite dipoles of other molecules.

Question 18

define hydrogen bonding

Answer 18

when hydrogen is bonded to N,O or F. This allows very strong attraction between molecules as the very positive hydrogen can attract negative areas of other molecules

Question 19

properties of covalent compounds

Answer 19

no electrical conduction (electrical neutral)

low points (weak dispersion)

soft and easily scratched (weak dispersion)

Question 20

if a covalent compounds has multiple bonds between atoms, its shape is always…

Answer 20

linear

Question 21

electron dot diagrams

Answer 21

are quick to draw

is not an accurate representation of molecular shape

Question 22

structural formulas

Answer 22

clearly shows number of covalent bonds in molecule

is not an accurate representation of molecular shape

Question 23

ball and stick model

Answer 23

shows the shape of the molecule

too complicated to draw

Question 24

space filling model

Answer 24

shows the relative sizes of atoms

too complicated to draw

Question 25

why does frozen water float on liquid water?

Answer 25

because the kinetic energy lost as the temperature drops allows more time for hydrogen bonds to form and create a neatly arranged shape. This shape is less dense than the liquid water because as liquid the molecules are constantly moving while still being bonded.

Question 26

why can water dissolve ionic compounds?

Answer 26

because of its polarity. The negatively charged oxygen atom attracts the cation and the positively charged hydrogens attract the anion, breaking the lattice apart and thus dissolving the substance.

Question 27

always remember to put….

Answer 27

LONE PAIRS ON DIAGRAMS