Chemical Bonding: Ionic Bonding Flashcards Preview

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Flashcards in Chemical Bonding: Ionic Bonding Deck (31):
1

what is ionic bonding?

electrostatic attraction between positive ions and negative ions

2

which groups are involved

occurs between a metal (group 1,2,3) and a non-metal (group 6,7)

3

why are electrons transferred?

to complete the outer shell 

4

how is ionic bonding represented?

in dot and cross diagrams

5

how is sodium chloride held together?

by strong electrostatic attraction

6

in sodium chloride is it called a chloride atom or a chlorine atom?

chloride

7

in energy released or absorbed when bonding occurs?

released

8

draw the dot and cross diagram for sodium chloride NaCl

 a single electron on outer shell of sodium has been transferred to chlorine

9

what is the noble gas structure significance?

 some ionic structures are similar to noble gas structures

e.g. magnesium oxide, sodium chloride

10

what is the struture of ionic bonds?

how is it held together?

 

giant ionic structures

a huge lattice of positive and negative ions packed together in a regular way

held together by the strong attractions between the positive and negative ions

11

what is a lattice?

a regular array of particles

12

what is the giant ionic structure of sodium chloride?

each sodium ion is touched by six chloride ions

each chloride ion is touched by six sodium ions

only ions joined together in Figure 4.12 are touching

this structure repeats itself over vast numbers of ions

(note the lines just show the arrangement of atoms)

13

although they have the exact same structure, is magnesium oxide's lattice held together by a stronger attraction that sodium chloride? why?

yes

the ions have a higher charge and therefore a higher attraction

14

do they tend to be hard or soft solids?

hard

15

do they tend to be crystalline? why?

because of the regular arrangement of ions in the lattice

some crystals are too small to be seen

e.g. magnesium oxide is seen as white powder because the individual crystals are too small to be seen by the naked eye

16

do they have high or low melting points and boiling points? why?

yes

because of the strong forces holding the lattice together

17

do they tend to be brittle or ductile?

brittle

because any small distortion of a crystal will bring ions with the same charge against each other

like charges repel and so the crystal splits itself in half

18

do they tend to be soluble or insolube in water? why?

soluble

although water is a covalent molecule, the electrons in the bond are attracted to the oxygen end of the bond

this makes oxygen slightly negative

this leaves hydrogen slightly short of electrons, therefore slightly positive

water is therefore described as a polar molecule

there are quite strong attractions between polar water molecules and the ions in the lattice

the slightly positive hydrogens in the water molecule cluster around the negative ions 

the slightly negative oxygens are attracted to the positive ions

the water molecules then pull the sodium chloride apart

magnesium oxide isn't soluble in water because the attractions between the ions aren’t strong enough to break the very powerful ionic bonds between magnesium and oxide ions

19

do they tend to be soluble or insoluble in organic substances? why?

soluble

organic solvents contain molecules which have much less distortion than there is in water

their molecules are less polar

there is not enough attraction between these molecules and the ions in the crystal to break the strong forces holding the lattice together 

20

what is conductivity?

flow of charge

flow of electrons/ions

21

do ionic substabces conduct electricity in solid state? why?

no because they don’t contain electrons that can move

they do conduct when molten or in dissolved in water because ions are free to move around

22

what are the uses of some ionic substances?

Sodium fluoride prevents tooth decay

Silver halides are used in photographic film

23

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28

the higher the charge the .... the melting point

the higher the charge the higher the melting point

29

what is the diagram for Potassium Fluoride, KF

30

what is the diagram for aluminium chloride, AlCl3

31

what is the diagram for Lithium Oxide, Li2O