Chapter 5 ionic and covalent bonding and structure

Question 1

Ionic compound definition

Answer 1

The electrostatic attraction between positive ions and negative ions

Question 2

Characteristics of ions

Answer 2

Oppositely charged ions attract each other strongly
The charge is spread over the whole ion so attracts the opposite from all directions

Question 3

physical structure of ionic compounds

Answer 3

Form closely packed, regular ionic lattice

Question 4

Structure of NaCl lattice

Answer 4

Each Na ion has six Cl ions surrounding it: 4 on the same layer and one above, one below. The same for Cl ions with Na

Question 5

Melting and boiling points of ionic compounds

Answer 5

High bc req alot of energy to overcome strong electrostatic forces between ions

Question 6

state of ionic compound at RT

Answer 6

solid

Question 7

Melting and boiling point of ionic compounds increase/ strength of ionic bond increases as..

Answer 7

charges of ions increase in size, when size of ions involved decrease

Question 8

Ionic compounds conduct when?

Answer 8

Molten or aqueous since ions are mobile charge carriers

Question 9

Ionic compounds normally dissolve in..

Answer 9

..polar solvents

Question 10

Covalent bonding?

Answer 10

Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 11

What is a covalent bond in relation to atomic orbitals?

Answer 11

The overlap of orbitals, each containing one electron to give a shared pair of electrons

Question 12

How do covalent bonds differ from the nature of ions attracting from all directions?

Answer 12

Covalent bons are localised, solely between the shared pair and the nuclei of the bonding electrons

Question 13

Name for a shared pair of electrons?

Answer 13

A bonded pair

Question 14

Name for a non-binding pair of electrons in a molecule?

Answer 14

Lone pair

Question 15

HONC rules?

Answer 15

The number of covalent bonds formed by the following:
Hydrogen=1
Oxygen=2
Nitrogen=3
Carbon=4

Question 16

Example of atoms that dont bond to adopt the structure of a group 8 atom

Answer 16

Boron triflouride, boron only has 3 outer shell electrons so can only bond to have a total of 6.
Compound which have expanded the octet

Question 17

Native bonds?

Answer 17

A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only. Uses an arrow in the displayed formula pointing away from the contributor

Question 18

Average bond enthalpy?

Answer 18

A measure of covalent bond strength: larger values have a greater strength.

Question 19

When is epansion of octet possible

Answer 19

In atoms with more than 2 shells (d block upwards) since there is only a max of 8 electrons available in the second shell

Question 20

expanding the octet

Answer 20

when a previously spin paired electron jumps to a higher, available shell meaning that there are more electrons available to form covalent bonds

Question 21

Why are ionic compounds solid at room temperature?

Answer 21

Insufficient energy to overcome strong electrostatic attraction between oppositely charged ions

Question 22

Examples of elements that commonly expand the octet

Answer 22

Sulphur, Phosphorus, Chlorine

Question 23

What dictates whether the octet is expanded and how many electrons are promoted?

Answer 23

the amount of energy supplied to the reaction

Question 24

Which of covalent or ionic bonds are stronger?

Answer 24

Covalent

Question 25

Carbon monoxide displayed formula

Answer 25

Two dashes between carbon and oxygen and one arrow leaving oxygen

Question 26

Heat energy iss called?

Answer 26

enthalpy

Question 27

Structure of ammonia?

Answer 27

Three single covalent bonds from N to Hs, one dative bond from N to H all in square bracket with plus charge

Question 28

What can be used to represent extra ions in the dot cross diagram of negatively charged polyatomic ions?

Answer 28

A triangle

Question 29

what are ions called when they are surrounded by water molecules (compound dissolved)

Answer 29

hydrated

Question 30

When will ionic compounds didsolve

Answer 30

If energy released by hydration of ions is greater than or equal to the energy required to overcome ionic bonds in the giant lattice