Bonding

Question 1

Define ionic bonding

Answer 1

Strong electrostatic FOA btw oppositely charged ions

Question 2

Why do ionic compounds have a high melting point?

Answer 2

• Lots of strong electrostatic FOA btw oppositely charged ions
• Forming giant ionic lattice
• Needs alot of energy to overcome bonds

Question 3

When can ionic compounds conduct electricity?

Answer 3

• Molten/ dissolved
• Ions are free to move + carry a charge

Question 4

Why do ionic compounds dissolve in water?

Answer 4

• Water molecules = polar (parts of molecule has small -ve charge + +ve charge)
• Charged parts pull ions away from lattice

Question 5

Sulfate

Answer 5

SO₄ ^2-

Question 6

Hydroxide

Answer 6

OH^-

Question 7

Nitrate

Answer 7

NO₃ ^-

Question 8

Carbonate

Answer 8

CO₃ ^2-

Question 9

Ammonium

Answer 9

NH⁴⁺

Question 10

Define covelant bond

Answer 10

Shared pair of e^-

Question 11

What are the 2 types of covelant structures?

Answer 11

• Molecular
• Giant covelant

Question 12

Define dative covelant

Answer 12

When 1 atom donates a shared pair of e^-

Question 13

Describe the structure of graphite + its properties

Answer 13

• Giant covelant
• High MP + insoluble - lots of strong covelant bonds need to be broken
• VDW btw layers allow layers to slide past each other
• Conducts electricity - delocalised e- are free to move + carry charge
• Low density - layers are far apart

Question 14

Describe the structure of diamond + its properties

Answer 14

• Giant covelant
• Shape: tetrahedral, C bonded to 4 C
• High MP, hard + insoluble - lots of strong covelant bonds
• Good thermal conducter - vibrations travel easily
• Can’t conduct electricity - outer e^- held in localised bonds

Question 15

Which type of bonding pair has the biggest angle?

Answer 15

• LP to LP
• Repel more than BP

Question 16

Define electronegativity

Answer 16

Power of an atom to attract pair of e^- in a covelant bond

Question 17

Define dipole

Answer 17

Diff in charge btw 2 atoms caused by shift in electron density in bond

Question 18

Explain why some molecules w/ polar bonds don’t have a permanent dipole

Answer 18

If polar bonds are arranged symmetrically, charges cancel out

Question 19

Explain how a permanent dipole occurs

Answer 19

E- distribution in covelant bond btw elements w/ diff. electronegativities will be unsymmetrical, produces polar bond

Question 20

Outline how Van der Waals are formed

Answer 20

• e^- movement in first molecule
• Induces dipole in another molecule
• δ+ attracts δ- in adjacent molecules

Question 21

What affects the strength of VDW?

Answer 21

• Longer chain - more e^- so stronger VDW
• Straight chain - lie closer together so stronger forces

Question 22

Outline how H bonds are formed

Answer 22

• F, N + O are v electronegative so draw bonding e- away from H
• Bond is polarised + H has high charge density
• Causes H atoms to form weak bonds w/ LP on F, O + N

Question 23

Define metallic bonding

Answer 23

Electrostatic FOA btw the +ve metal ions and the delocalised electrons

Question 24

Outline the properties of metals

Answer 24

• High MP - lots of electrostatic FOA btw +ve metal + sea of delocalised e^- - more DE, stronger the bond
• Good thermal conducter - DE pass kinetic energy
• Good electrical conducter - DE move + carry current
• Insoluble

Question 25

Outline the factors affecting the strength of metallic bonding

Answer 25

* **No. protons** - **more protons** = stronger bond * **No. DE per atom** - **more DE** = stronger bond * **Size of ions** - **smaller ion** = stronger bond

Question 26

Why do simple covelant molecules have low MP + BP?

Answer 26

Only have to **break IMF BTM, not covelant bonds**

Question 27

**Ionic** Eg. MP + BP State at room temp Does solid conduct electricity Does liquid conduct electricity Is it soluble in water

Answer 27

* **NaCl** * **High** * **Solid** * **No** * **Yes** * **Yes**

Question 28

**Simple covelant** Eg. MP + BP State at room temp Does solid conduct electricity Does liquid conduct electricity Is it soluble in water

Answer 28

* **CO₂, I₂** * **Low** * **I₂ is solid but usually liquid + gas** * **No** * **No** * **Depends on polarity**

Question 29

**Giant covelant** Eg. MP + BP State at room temp Does solid conduct electricity Does liquid conduct electricity Is it soluble in water

Answer 29

* **Diamond, graphite** * **High** * **Solid** * **No exp. graphite** * **Sublimes, doesn't melt** * **No**

Question 30

Metallic Eg. MP + BP State at room temp Does solid conduct electricity Does liquid conduct electricity Is it soluble in water

Answer 30

* **Fe, Mg** * **High** * **Solid** * **Yes** * **Yes** * **No**