Shapes of Molecules and Intermolecular Forces

Question 1

how many bonded/lone pairs and bond angle in a pyramidal

Answer 1

3 bonded pairs, one lone pair , 107 degrees

Question 2

how many bonded/lone pairs and bond angle in a non-linear shape

Answer 2

2 bonded pair , 2 lone pair , 104.5 degrees

Question 3

how many bonded/lone pairs and bond angle in a linear shape

Answer 3

2 bonded pairs , 180 degrees

Question 4

ow many bonded/lone pairs and bond angle in trigonal planar

Answer 4

3 bonding pairs, 120 degrees

Question 5

how many bonded/lone pairs and bond angle in octrahedral

Answer 5

6 bonding pairs , 90 degrees

Question 6

what is electronegativity?

Answer 6

attraction of a bonded atom for the shared pair of electrons in a covalent bond

Question 7

how does electronegativity change across periodic table?

Answer 7

nuclear charge increases and atomic radius decreases

Question 8

what are the most electronegative atoms?

Answer 8

non metals , nitrogen, oxygen , fluorine, chlorine

Question 9

what are the least electronegative atoms?

Answer 9

group 1 metals including lithium , sodium , potassium,

Question 10

what is the electronegativity difference in each bond type?

Answer 10

covalent = 0
polar covalent = 0-1.8
ionic = greater than 1.8

Question 11

when is a bond non-polar

Answer 11

1) if bonded atoms are the same ( pure covalent bond)
2) if bonded atoms have similar or same electronegativity

Question 12

what is a polar covalent bond?

Answer 12

a bond will be polar when the bonded atoms are different and have different electronegativity values

Question 13

how are induced dipole-dipoled formed

Answer 13

movement of electrons produce an instananeous dipole which induces a dipole on a neighbouring molecule. The induced dipole induces further dipoles on neighbouring molecules which then attract one another

Question 14

which element has higher boiling point ( helium , 2 electrons) ( neon, 10 electrons) ( argon, 18 electrons)

Answer 14

argon has highest boiling point as there are more electrons so larger instantaneous and induced dipoles therefore greater induced dipole-dipole interactions and attractive forces between molecules as a result more energy needed to oversome the intermolecular forces.

Question 15

what is the solubility of non-polar molecular substances

Answer 15

when added to non-polar solvent, intermolecular forces form weakening intermolecular forces in the molecular lattice which breaks it down and dissolves
insoluble in polar solvents as intermolecular bonding in polar solvent is too strong to be broken

Question 16

what is the electric conductivity in simple molecular structures?

Answer 16

no mobile charged particles in simple molecular structures therefore cannot complete an electrical circuit

Question 17

what are the anomalous properties of water ?

Answer 17

1) ice is less dense than water
2) water has relatively high mp and bp
3)relatively high surface tension and viscosity so insects walk on pond surfaces

Question 18

why is ice less dense than water?

Answer 18

hydrogen bonds hold water molecules in an open lattice structure which are more further apart in water therefore ice is less dense than water