Section 3 - Bonding

Question 1

What is Ionic Bonding?

Answer 1

Bonding that occurs between Metals and Non-Metals, when ions are held together by electrostatic attraction.

Question 2

How are ions formed?

Answer 2

When one or more electrons are transferred from one atom to another.

Question 3

Do metals lose or gain electrons when they become ions?

Answer 3

They lose them.

Question 4

Do non-metals lose or gain electrons when they become ions?

Answer 4

They gain them.

Question 5

What is the formula for a sulfate ion?

Answer 5

SO₄²⁻

Question 6

What is the formula for a hydroxide ion?

Answer 6

OH⁻

Question 7

What is the formula for a nitrate ion?

Answer 7

NO₃⁻

Question 8

What is the formula for a carbonate ion?

Answer 8

CO₃²⁻

Question 9

What is the formula for a ammonium ion?

Answer 9

NH₄⁺

Question 10

What is the structure of an ionic bond?

Answer 10

A giant ionic lattice.

Question 11

What is the melting point of ionic bonds?

Answer 11

High - lots of strong forces of attraction between +ive and -ive ions.

Question 12

Are ionic lattices good conductors of electricity?

Answer 12

Yes.

Question 13

How do you make a giant ionic lattice conduct electricity?

Answer 13

Make the ions move by heating it up or dissolving it if it can be dissolved.

Question 14

Why do giant ionic lattices need to be molten or dissolved to conduct electricity?

Answer 14

In a solid the ions are fixed by strong ionic bonds.

They need to be free to move and carry a charge.

Question 15

Do ionic compounds dissolve in water?

Answer 15

Generally yes - water molecules are polar and the charged parts on them pull ions away from the lattice.

Question 16

What is the order of mpts in LiCl, LiBr and LiF? And why?

Answer 16

Because LiF is the smallest so has the strongest FoA.

Question 17

How many Cl- ions is each Na+ bonded to?

Answer 17

6

Question 18

What is Covalent Bonding?

Answer 18

Bonding that occurs between non-metals, when two or more atoms share a pair of electrons.

Question 19

What is a co-ordinate/dative covalent bond?

Answer 19

A shared pair of electrons provided by one atom.

Question 20

What are the two types of covalent bonds?

Answer 20

Molecular and Giant Covalent.

Question 21

What are giant covalent structures?

Answer 21

Huge networks of covalently bonded atoms.

Question 22

What is the structure of graphite?

Answer 22

• Each carbon is covalently bonded to 3 other carbons.

- The 4th outer electron of each carbon is delocalised.

Question 23

What are the properties of graphite?

Answer 23

• Soft and brittle - layers slide.
• Conducts electricity - free electrons.
• Low density - layers are far apart.
• Very high mpt - very strong covalent bonds.
• Insoluble - covalent bonds are too strong to break.

Question 24

What is the shape of graphite?

Answer 24

• Hexagonal planar sheets of bonded carbons.

- Delocalised electrons and Van der Waals between layers.

Question 25

What is the structure of Diamond?

Answer 25

- Each carbon is bonded to 4 other carbons. | - Not layered.

Question 26

What are the properties of diamond?

Answer 26

- Doesn't conduct electricity - no free electrons. - Insoluble - covalent bonds are too strong to break. - Very high mpt - very strong covalent bonds. - Extremely hard.

Question 27

What is the shape of diamond?

Answer 27

It is arranged in a tetrahedral shape.

Question 28

What is the structure of Iodine?

Answer 28

It is molecular. | Pairs of iodine atoms are covalently bonded and held together by weak intermolecular forces.

Question 29

What is Iodine's mpt/bpt?

Answer 29

Low - only need to overcome weak IMFs.

Question 30

What is the structure of Ice?

Answer 30

It is molecular - H2O molecules are held together by IMFs between Hs and Os.

Question 31

What is the shape of a molecule/ion with 2 bonding pairs of electrons? And what is the bond angle?

Answer 31

Linear. 180.

Question 32

What is the shape of a molecule/ion with 3 bonding pairs of electrons? And what is the bond angle?

Answer 32

Trigonal Planar. 120.

Question 33

What is the shape of a molecule/ion with 2 bonding pairs and 1 lone pair of electrons? And what is the bond angle?

Answer 33

Bent. 117.5.

Question 34

What is the shape of a molecule/ion with 4 bonding pairs of electrons? And what is the bond angle?

Answer 34

Tetrahedral. 109.5.

Question 35

What is the shape of a molecule/ion with 3 bonding pairs and 1 lone pair of electrons? And what is the bond angle?

Answer 35

Trigonal Pyramid. 107.

Question 36

What is the shape of a molecule/ion with 2 bonding pairs and 2 lone pairs of electrons? And what is the bond angle?

Answer 36

Bent. 104.5.

Question 37

What is the shape of a molecule/ion with 5 bonding pairs of electrons? And what are the 2 bond angles?

Answer 37

Trigonal Bipyramid. 90 and 120.

Question 38

What is the shape of a molecule/ion with 4 bonding pairs and 1 lone pair of electrons? And what are the 2 bond angles?

Answer 38

Seesaw. 87.5 and 117.5.

Question 39

What is the shape of a molecule/ion with 3 bonding pairs and 2 lone pairs of electrons? And what is the bond angle?

Answer 39

Trigonal Planar. 120. (lone pairs working in equal and opposite directions cancel each other out) Or T-shape. 85.

Question 40

What is the shape of a molecule/ion with 6 bonding pairs of electrons? And what is the bond angle?

Answer 40

Octahedral. 90.

Question 41

What is the shape of a molecule/ion with 5 bonding pairs and 1 lone pair of electrons? And what is the bond angle?

Answer 41

Helicopter. 87.5.

Question 42

What is the shape of a molecule/ion with 4 bonding pairs and 2 lone pairs of electrons? And what is the bond angle?

Answer 42

Square Planar. 90.

Question 43

What is a good method for working out shapes of molecules?

Answer 43

- Add group number to number of bonds to charge. (a negative charge is a +1 and positive is -1)!!!! - Divide answer by 2 to get number of pairs. - Calculate how many bonded pairs and how many lone pairs.

Question 44

What is the most electronegative element?

Answer 44

Fluorine.

Question 45

What is the general trend in electronegativity?

Answer 45

Increases across periods. | Decreases down groups.

Question 46

What is a polar bond?

Answer 46

A bond between two atoms of different electronegativities where the electron pair is pulled closer to the more electronegative atom.

Question 47

Is H2 polar?

Answer 47

No - it's non-polar.

Question 48

Is C-H polar?

Answer 48

No - C and H have practically the same electronegativity.

Question 49

How are permanent dipoles formed?

Answer 49

In a polar bond, the difference in electronegativity causes a delta positive and a delta negative charge.

Question 50

What is a polar molecule?

Answer 50

It is a molecule with polar bonds, which causes an uneven distribution of charge across the molecule.

Question 51

What happens if polar bonds are symmetrical in a molecule?

Answer 51

The molecule will be non-polar - the charges cancel out.

Question 52

What are the 3 types of IMFs?

Answer 52

1) Van der Waals 2) Permanent dipole-dipole forces 3) Hydrogen Bonding

Question 53

What are Van der Waal forces?

Answer 53

Instantaneous dipole dipoles.

Question 54

Define electronegativity

Answer 54

The ability of an atom to attract a pair of electrons in a covalent bond.

Question 55

When can Hydrogen Bonding occur?

Answer 55

When H is covalently bonded to N O or F.

Question 56

How is a dipole formed?

Answer 56

When electrons are grouped more on one side of an atom than the other for an instant.

Question 57

How do Van der Waals forces form?

Answer 57

An instant dipole causes an instant dipole on a neighbouring atom which causes an instant dipole on the next atom, etc. This causes a constant attraction.

Question 58

Why might a molecule have stronger VdWs and therefore higher mpts?

Answer 58

- Larger molecules = larger electron clouds = stronger VdWs | - Long straight molecules can lie closer together = stronger VdWs

Question 59

What is the strength order of IMFs?

Answer 59

- Hydrogen Bonding - Dipole Dipole - Van der Waals

Question 60

How does Hydrogen Bonding occur?

Answer 60

- N, O and F are very electronegative - They draw electrons away from H creating a polar bond. - H has such a high charge density that the atoms form weak bonds with lone pairs on the N O or F.

Question 61

What is the structure of metallic bonding?

Answer 61

- Giant Metallic Lattice - The outer shell of electrons of a metal atom is delocalised. - There is an attraction between positive metal ions and a sea of delocalised electrons.

Question 62

What are the properties of a metallic bond?

Answer 62

- High melting point - strong FoA - The more delocalised electrons, the higher the mpt. - Good conductors of heat and electricity - electrons can carry a current. - Soft/malleable - layers can slide. - Insoluble (except liquid metals) - too strong.