1.3 Structure and Bonding

Question 1

what is ionic bonding?

Answer 1

• electrostatic force of attraction between oppositely charged ions

Question 2

what is a covalent bond?

Answer 2

• shared pair of electrons

Question 3

what is dative covalent bonding?

Answer 3

• a shared pair of electrons in the covalent bond come from only one of the bonding atoms.
• NH4+, H3O+ , NH3BF3

Question 4

what is metallic bonding?

Answer 4

• electrostatic force of attraction between the positive metal ions and delocalised electrons

Question 5

what are the three main factors that affect the strength of metallic bonding?

Answer 5

• number of protons, more protons stronger the bond
• number of delocalised electrons, more electrons stronger bond
• size of ion, smaller the stronger

Question 6

why are metals malleable?

Answer 6

• positive ions in the lattice are all identical
• planes of ions can slide easily over one another

Question 7

how do you explain the shape of a molecule?

Answer 7

• state number of bonding pairs and lone pairs of electrons
• state that the electron pairs repel and try to get as far apart as possible
• if there are no lone pairs state the electron pairs repel equally
• if there are lone pairs of electrons, state that lone pairs repel more than bonding pairs

Question 8

how much do lone pairs repel bonding pairs by

Answer 8

2.5 degrees bond angle

Question 9

what is electronegativity?

Answer 9

• the power of an atom to attract a lone pair of electrons within a covalent bond

Question 10

what happens to electronegativity across a period

Answer 10

• increases
• number of protons increases and atomic radius decreases

Question 11

what happens to electronegativity down a group?

Answer 11

• decreases
• distance between the nucleus and outer electrons increases
• shielding of inner electrons increases

Question 12

how can you determine the bonding present via electronegativity

Answer 12

• compound containing elements of similar electronegativity will be purely COVALENT
• compound containing elements of very different electronegativity and a large difference will be IONIC

Question 13

how does a permanent dipole form

Answer 13

• elements in the bond have different electronegativities
• of around 0.3 to 1.7

Question 14

why does the charge seperation occur on a permanent dipole

Answer 14

• because of unequal distribution of electrons in the bond

Question 15

why are symmetrical molecules non polar

Answer 15

• because the individual dipoles cancel out, due to the symmetrical shape of the molecule
• so there is no net dipole moment

Question 16

what are the main factors affecting size of van der waals

Answer 16

• more electrons there are, the higher the chance the temporary dipoles will form
• size of molecule

Question 17

what is the order of intermolecular forces in terms of strength

Answer 17

• hydrogen bonding
• dipole - dipole forces
• Van der Waals

Question 18

how do van der waal forces arise?

Answer 18

• temporary fluctuations in electron distribution, create a temporary dipole
• this induces a corresponding dipole in nearby molecules, leading to weak attraction

Question 19

how do permenant dipole dipole forces arise?

Answer 19

• permenant dipoles arise when there is a difference in electronegativity between atoms in a molecule, leading to uneven distribution of electron density
• dipole-dipole forces arise when the positive end of a permenant dipole is attracted to the negative end of another permenant dipole

Question 20

how does hydrogen bonding arise?

Answer 20

• hydrogen atom covalently bonded to O,N,F
• lone pair of electrons must be present
• hydrogen bond formed between partially positive hydrogen atom and lone pair of electronegative atom