Bonding

Front 1

What is an ionic bond?

Back 1

An ionic bond is the electrostatic force of attraction between oppositely charged ions forced by electron transfer.

Front 2

What is a covalent bond?

Back 2

A covalent bond is a shared pair of electrons.

Front 3

What is a Dative covalent bond?

Back 3

A Dative covalent bond forms when the shared pair of electrons in the covalent bond come from only one of the bonding atoms.

Front 4

What is the other name for the dative covalent bonding?

Back 4

Coordinate bonding.

Front 5

What is a metallic bond?

Back 5

A metallic bond is the electrostatic force of attraction between the positive metal ions and the delocalised electrons.

Front 6

What are the three main factors that affect the strength of a metallic bond?

Back 6

The more protons, the stronger the bond.

The more delocalised electrons, the stronger the bond.

The smaller the ion, the stronger the bond.

Front 7

What is the structure of an ionic compound?

Back 7

Giant ionic lattice.

Front 8

What is the structure of a simple molecular compound?

Back 8

With intermolecular forces between molecules.

Front 9

What is the structure of a macromolecule?

Back 9

Giant molecular structures.

Front 10

What is the structure of a metal?

Back 10

Giant metallic lattice.

Front 11

Describe the boiling and melting points of an ionic compound

Back 11

They are very high because an ionic compound is a giant lattice of ions with strong electrostatic forces between oppositely charged ions.

Front 12

Describe solubility of ionic compounds in water

Back 12

Generally good.

Front 13

Describe the conductivity of an ionic compound when solid

Back 13

Poor as the ions can’t move as they are in a fixed lattice which means that they can’t carry charge, so they can’t conduct electricity.

Front 14

Describe the melting and boiling points of a molecular compound

Back 14

The melting and boiling points of a molecular compound are very low because of the weak intermolecular forces between molecules.

Front 15

Describe the solubility of molecular compounds in water

Back 15

Generally poor.

Front 16

Describe the conductivity of molecular compounds when solid

Back 16

Poor as there are no ions to conduct and the electrons are localised.

Front 17

Describe the conductivity of molecular compounds when molten

Back 17

Poor as there are no ions.

Front 18

Describe the melting and boiling points of macromolecular compounds

Back 18

The melting and boiling points of macromolecular compounds are generally high because of many strong covalent bonds which require a lot of energy to overcome.

Front 19

Describe the solubility of macromolecular compounds in water

Back 19

Insoluble.

Front 20

Describe the conductivity of macromolecular compounds when solid

Back 20

Diamond and sand are poor because their electrons can’t move. Graphite is good as free delocalised electrons between layers.

Front 21

Describe the conductivity of macromolecular molecular compounds when molten

Back 21

Poor.

Front 22

Describe the melting and boiling points of metals

Back 22

High as there are strong electrostatic forces between the positive metal ions and a sea of delocalised electrons.

Front 23

Describe the solubility of metals in water

Back 23

Insoluble.

Front 24

Describe the conductivity of metals when solid

Back 24

Good as delocalised electrons can move through the structure.

Front 25

Describe the conductivity of metals when molten

Back 25

Good.

Front 26

How many bonding pairs does Linear have?

Back 26

2.

Front 27

How many lone pairs does Linear have?

Back 27

0.

Front 28

What is the bond angle of Linear?

Back 28

180°.

Front 29

How many bonding pairs does Trigonal planar have?

Back 29

3.

Front 30

How many lone pairs does Trigonal planar have?

Back 30

0.

Front 31

What is the bond angle of Trigonal planar?

Back 31

120°.

Front 32

How many bonding pairs does Tetrahedral have?

Back 32

4.

Front 33

How many lone pairs does Tetrahedral have?

Back 33

0.

Front 34

What is the bond angle of Tetrahedral?

Back 34

109.5°.

Front 35

How many bonding pairs does Trigonal pyramidal have?

Back 35

3.

Front 36

How many lone pairs does Trigonal pyramidal have?

Back 36

1.

Front 37

What is the bond angle of Trigonal pyramidal?

Back 37

107°.

Front 38

How many bonding pairs does Bent have?

Back 38

2.

Front 39

How many lone pairs does Bent have?

Back 39

2.

Front 40

What is the bond angle of Bent?

Back 40

104.5°.

Front 41

How many bonding pairs does Trigonal Bipyramidal have?

Back 41

5.

Front 42

How many lone pairs does Trigonal Bipyramidal have?

Back 42

0.

Front 43

What is the bond angle of Trigonal Bipyramidal?

Back 43

120° and 90°.

Front 44

How many bonding pairs does Octahedral have?

Back 44

6.

Front 45

How many lone pairs does Octahedral have?

Back 45

0.

Front 46

What is the bond angle of Octahedral?

Back 46

90°.

Front 47

How do you explain shape?

Back 47

1) State numbed of bonding pairs and lone pairs of electrons.

2) State that electron pairs repel and try to get as far apart as possible.

3) If there are no lone pairs state that the electron pairs repel equally.

4) If there are lone pairs of electrons, then state that lone pairs repel more than bonding pairs.

5) State actual shape and bond angle.

Front 48

Where do Van der Waals forces occur?

Back 48

All molecular substances and noble gases.

Front 49

Where don’t Van der Waals forces occur?

Back 49

Ionic substances.

Front 50

How are induced dipoles formed?

Back 50

In any molecule the electrons are moving constantly and randomly. As this happens the electron density can fluctuate, and parts of the molecule become more or less negative. These instantaneous dipoles can cause dipoles to form in neighbouring molecules.

Front 51

What is electronegativity?

Back 51

Electronegativity is the relative tendency of an atom in a covalent bond in a molecule to attract electrons in a covalent bond to itself.

Front 52

How is electronegativity measured?

Back 52

Electronegativity is measured on the Pauling scale.

Front 53

What is the pattern of electronegativity across a period?

Back 53

Electronegativity increases across a period as the number of protons increases and the atomic radius decreases because the electrons in the same shell are pulled in more.

Front 54

What is the pattern of electronegativity down a group?

Back 54

Electronegativity decreases down a group because the distance between the nucleus and the outer electrons increases and the shielding of inner electrons increases.

Front 55

How does electronegativity affect covalent bonding?

Back 55

A compound containing elements of similar electronegativity and hence a small electronegativity different will be purely covalent.

Front 56

How does electronegativity affect ionic bonding?

Back 56

A compound containing elements with very different electronegativity and hence a very large electronegativity difference will be ionic.

Front 57

What is a polar covalent bond?

Back 57

A polar covalent bond forms when the elements in the bond have different electronegativities.

Front 58

What is a symmetrical molecule?

Back 58

A symmetrical molecule is a molecule that has identical bonds and no lone pairs of electrons.

Front 59

Why aren’t symmetrical molecules polar even if individual bonds within the molecules are polar?

Back 59

The individual dipoles on the bonds ‘cancel out’ due to the symmetrical shape of the molecule. There is no net dipole moment: the molecule is non-polar.

Front 60

What is the sign of the induced dipole?

Back 60

The induced dipole is always the opposite sign to the original one.

Front 61

What is the main factor affecting the size of the Van der Waals?

Back 61

The more electrons there are in the molecule the higher the chance that temporary dipoles will form. This makes the Van der Waals stronger between the molecules and so boiling points will be greater.

Front 62

Why does the boiling point of Halogen increase down the group 7 series?

Back 62

The number of electrons increases as you go down the group as the molecules get bigger causing an increase in the size of the Van der Waals between the molecules. This is why I2 is a solid whereas Cl2 is a gas.

Front 63

How can the shape of the molecule have an effect on the size of Van der Waals forces?

Back 63

Long chain alkanes have a larger surface area of contact between molecules for Van der Waals to form than compared to spherical shaped branched alkanes and so have stronger Van der Waals.

Front 64

Describe permanent dipole-dipole forces

Back 64

Permanent dipole-dipole forces occurs between polar molecules. It is stronger than Van der Waals and so the compounds have higher boiling points. Polar molecules have a permanent dipole. Polar molecules are asymmetrical and have a bond where there is a significant difference in electronegativity between the atoms.

Front 65

Describe hydrogen bonding

Back 65

It occurs in compounds that have a hydrogen atom attached to one of the three most electronegative atoms of nitrogen, oxygen and fluorine, which most have an available lone pair of electrons. There is a large electronegativity difference between the H and the O, N and F.