6. Shapes of Molecules and IMFs

Question 1

What is the order of repulsion between pairs?

Answer 1

bp-bp < bp-lp < lp-lp

Question 2

Name the different bond shapes

Answer 2

linear, pyramidal, trigonal planar, tetrahedral, octahedral

Question 3

How many bonded pairs does a compound with an octahedral shape have?

Answer 3

6

Question 4

What happens in terms of nuclear charge and atomic radius across the periodic table L=>R

Answer 4

nuclear charge : increases

atomic radius : decreases

Question 5

Which are the most electronegative elements?

Answer 5

N, O, F, Cl

Question 6

At what point does a polar covalent bond become ionic?

Answer 6

when electronegativity difference is greater than 1.8

Question 7

What is a pure covalent bond?

Answer 7

one where no electronegativity difference is involved

Question 8

What is a polar covalent bond?

Answer 8

when bonded atoms are different and have different electronegativity values
leads to 1 atom having a greater attraction towards the bonding pair than the other

Question 9

When is a covalent substance non-polar?

Answer 9

if there are no polar bonds

if the dipoles cancel each other out i.e. the molecule is symmetrical

Question 10

How do LDFs work?

Answer 10

instantaneous dipole shifting
induced dipole in next molecule
attract neighbouring molecules together

Question 11

What happens to IMFs when the number of electrons in a substance increases?

Answer 11

larger instantaneous and induced dipoles
therefore greater amount of induced dipole dipole interactions
therefore stronger attractive forces between molecules