Bonding

Question 1

Define average bond enthalpy

Answer 1

A measurement of covalent bond strengths

Question 2

What are the six bonds shapes we need to know?

Answer 2

• Linear
• Trigonal planar
• Tetrahedral
• Pyramidal
• Non-linear
• Octrahedral

Question 3

Define Linear and give an example

Question 4

Define trigonal and give an example

Question 5

Octaheral shape - 6 bonds with an angle of 90 degrees between each one

Question 6

Describe tetrahedral and give an example

Question 7

Describe pyramidal and give an example

Question 8

Describe non-linear and give an example

Answer 8

2 bonded pairs and 2 lone pairs. the 2 lone pairs push the bonded pairs even closer otgether reducing the angle to 104.5 (change of 2.5 degrees each time) H2O

Question 9

Describe octaheral

Answer 9

6 bonds with an angle of 90 degrees between each one

Question 10

What is electron pair repulsion?

Answer 10

When the lone pairs are closer to the central atom so repel more strongly than the bonded pair

Question 11

Define electronegativity

Answer 11

The ability of an atom to attract the bonding electrons in a covalent bond. It increaces up the periodic table and across to the right of the periodic table meaninf flourine is the most elcronegative

Question 12

What is the difference of electronegativity in a covalent bond

Answer 12

0

Question 13

What is the difference of electronegativity in a polar bond?

Answer 13

0-1.8

Question 14

What is the difference of electronegativity in an ionic bond?

Answer 14

1.8 as the large difference in electronegativity means that the stronger atom will gain control of the electrons creating a postive na dnegative ions

Question 15

What are permanent dipoles and where do they occur?

Answer 15

Delta positive or LISTEN TO THIS BIT AGAIN before 3.19

Question 16

What are intermolecular forces?

Answer 16

The attractions between dipoles which create the physical properities of a molecule

Question 17

Name the intermolecular forces and their strengths

Answer 17

Hydrogen bonds - strongest
Permaanent dipole interactions - Stronger that induced, weaker than hydrogen bonds
Induced dipole interactions - weakest

Question 18

What are induced dipole-dipole forces also known as?

Answer 18

London forces and Van der waals forces. They are when instantaneously electrons move closer or further away to atoms creating instantaneous dipoles which then create a ripple effect on neighbouring molecules creating dipoles that only last for a second

Question 19

hydrogen bonding is a permanent dipole between a hydrogen atom and either flourine, oxygen or nitrogen. It is hydrogen bonding that gives water its unusual properties for example ice is less dense than water, ususually high melting anf boiling points and high surface tension and viscousity

Question 20

Define simple molecular lattices

Answer 20

When molecules are held together by weak inermolecular forces, the atomw within the molcule are held together by very strong covalent bonds. These lattices have low melting and boiling points because they will easily break up into their individual moecules due to the weak forcees between them. They dont conduct electricity because the molecules are all held togetherindividually so there are no charges available

Question 21

Non-polar molecules (molecules without a charge) will be soluble in non-polar solvents because the interactions will weaken the intermolecular forces and cause it to break up and dissolve. However non-polar molecules are insoluble in polar solvents because the polar bonds are too strong to break so there’s no interaction between the molecules and solvent
Polar substances are soluble on polar solvents