1.4 Bonding

Question 1

what is ionic bonding

Answer 1

an electrostatic attraction between oppositley charged ions

Question 2

what is an ionic crystal

Answer 2

-lattice of ions
-held together by electrostatic attraction of oppositely charged ions

Question 3

Why do ionic compounds have high melting points

Answer 3

• strong electrostatic attraction between oppositely charged ions require lots of energy to break
• therefore they have high melting points

Question 4

What is a covalent bond

Answer 4

• involves the sharing of electron pairs between atoms
• forms due to electrostatic attraction between the positive nuclei of the bonded atoms and the negative electrons which are between the two nuclei

Question 6

What is ionic bonding found between

Answer 6

non-metal + metal

Question 7

What is ionic bonding found between

Answer 7

non-metal + metal

Question 8

What is covalent bonding found between

Answer 8

non metal + non-metal

Question 9

What is metallic bonding found between

Answer 9

metal + metal

Question 10

why are metals conductive?

Answer 10

due to the sea of delocalised electrons

Question 11

what is the point of chemical bonding

Answer 11

chemical bonding occurs for atoms to get a stable electron configuration

Question 12

define a chemical bond

Answer 12

a chemical bond is an electrostatic force of attraction between elements with a positive and negative charge

Question 13

giant covalent

Answer 13

high melting point

Question 14

simple covalent

Answer 14

low melting point (small molecules)

Question 15

how to drawn ionic bonding

Answer 15

dot and cross diagram

Question 16

how to draw covalent bonding

Answer 16

dot and cross diagram but with overlapping orbital

Question 17

Why is a covalent bond formed

Answer 17

By sharing a pair of electrons (each electron donates an electron each to the shared pair)

Question 18

What is bond polarity

Answer 18

separation of electric charge along a bond.
polar bonds occur when electrons in the bond are not shared equally

Question 20

Electronegativity

Answer 20

The ability of an atom to attract the shared pair of electrons (electron density) in a covalent bond towards itself

Question 21

Factors that affect Electronegativity

Answer 21

• nuclear charge
• atomic radius
• shielding

Question 22

Electronegativity trend across a group:

Answer 22

• increases across a group

Question 23

Electronegativity down a period

Answer 23

• Decreases down a period

Question 24

What properties cause a dipole bond to form

Answer 24

The electronegativities of the elements are different

Question 25

What bond occurs when there is no dipole?

Answer 25

pure covalent

Question 26

what bond occurs when there is a dipole?

Answer 26

polar covalent

Question 27

where will delta- go?

Answer 27

The more electronegative

Question 28

where will delta+ go?

Answer 28

The least electronegative

Question 29

What is a temporary dipole

Answer 29

an uneven distribution of electrons, making one half of the molecule more negatively charged than the other

Question 30

What is a permanent dipole

Answer 30

• when 2 covalently bonded atoms have different electronegativities, forming a polar bond. This causes a delta- and delta+ region

Question 31

What is an induced dipole

Answer 31

created when electron distribution around a molecule is influenced by a charged particle

Question 32

Compare the bond character in a covalent bond and ionic bond

Answer 32

covalent bond - electrons equally shared between atoms, no overall charge

ionic bond - complete transfer of electrons between atoms to produce ions will full charges

Question 33

what type of intermolecular forces are there

Answer 33

• Temporary dipole
• Permanent dipole
• Hydrogen bonding

Question 35

what is a dipole

Answer 35

A molecule with 2 different charges

Question 36

hydrogen bonding

Answer 36

permanent dipole-dipole but occurs when a H is bonded to:
- fluorine
- oxygen
- nitrogen

Question 37

Strength of intermolecular forces:

Answer 37

h-bonding > permanent dipole-dipole > van der Waals’

this means that H-bonding has a higher boiling point.

Question 38

what is a lone pair of electrons

Answer 38

a pair of electrons in a valence shell that are no involved in bonding

Question 39

What happens to boiling points across a group

Answer 39

they increase

Question 40

why do boiling point increase across a group

Answer 40

• number of electron increase
• strength of intermolecular forces increase (more electrons = greater strength)

Question 41

why are boiling points of Group 4 hydrides lower than hydrides of Groups 5, 6 and 7

Answer 41

5, 6 and 7 are more likely to have dipole-dipole