BLOCK 2 Bonding

Question 1

Define electronegativity

Answer 1

A measure, the measure of the ability an atom to attract a shared pair of electrons in a covalent bond

Question 2

Why does electronegativity increase across a period?

Answer 2

Increase in:
- nuclear charge
- atomic radius

Question 3

define a covalent bond

Answer 3

A shared pair of electrons within a bond
Where bond electrons have opposing spin

Question 4

forces between molecules generally influence their

Answer 4

Physical properties

Question 5

forces inside molecules generally influence their

Answer 5

chemical properties

Question 6

order of bond strength
(from strongest to weakest)

Answer 6

-pure covalent
-ionic
-nonpolar covalent
-polar covalent
-hydrogen
-van der waals

Question 7

Name the top four electronegative elements

Answer 7

-F
-O
-N
-Cl

Question 8

name physical properties

Answer 8

-solubility
-conductivity
-m.p , b.p
-state at room temp

Question 9

name chemical properties

Answer 9

-reactivity

Question 10

what is intermolecular

Answer 10

forces between molecules

Question 11

what is intramolecular

Answer 11

forces inside molecules

Question 12

name intermolecular forces

Answer 12

-van der Waal’s
-dipole/dipole
-hydrogen bonds

Question 13

name intramolecular forces

Answer 13

-ionic
-covalent
-metallic

Question 14

name all covalent bonds

Answer 14

-pure
-nonpolar
-polar
-co-ordinate

Question 15

what is a chemical bond?

Answer 15

an electrostatic force of attraction between atoms.
All electrostatic bonds refer to a +/- attraction

Question 17

what is ionic bonding

Answer 17

an electrostatic attraction between oppositley charged ions

Question 18

What is ionic bonding found between

Answer 18

non-metal + metal

Question 19

What is covalent bonding found between

Answer 19

non metal + non-metal

Question 20

What is metallic bonding found between

Answer 20

metal + metal

Question 21

Why is a covalent bond formed

Answer 21

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

Question 22

Factors that affect Electronegativity

Answer 22

• nuclear charge
• atomic radius
• shielding

Question 23

Electronegativity trend across a group:

Answer 23

• increases across a group

Question 24

Electronegativity down a period

Answer 24

• Decreases down a period

Question 25

What properties cause a dipole bond to form

Answer 25

The electronegativities of the elements are different

Question 26

What bond occurs when there is no dipole?

Answer 26

pure covalent

Question 27

what bond occurs when there is a dipole?

Answer 27

polar covalent

Question 28

What is a temporary dipole

Answer 28

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

Question 29

What is a permanent dipole

Answer 29

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

Question 30

more more more

Answer 30

more ELECTRONS more VAN DER WAAL'S more HEAT

Question 31

what is a polar bond

Answer 31

a separation of charge due to unequal sharing of electrons

Question 33

what is a dipole

Answer 33

A molecule with 2 different charges

Question 34

hydrogen bonding

Answer 34

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

Question 35

Strength of intermolecular forces:

Answer 35

h-bonding > permanent dipole-dipole > van der Waals' this means that H-bonding has a higher boiling point.

Question 36

what is a lone pair of electrons

Answer 36

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

Question 37

What happens to boiling points across a group

Answer 37

they increase

Question 38

why do boiling point increase across a group

Answer 38

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