Aims

Class work 29 June 2007Ions

LO’s• What are ions?

Write it down!! Page 43/44© C Meyer

All• Know elements react to form

compounds• Know the layout of the periodic

table• Know what an ion is• Know group 1 reacts with Group 7Most/Some• Explain how ions form• Work out the charge on an ion

Aims

• What are the properties of Sodium?

• What are the properties of Chlorine?

What are ions?

Demo Na/Cl reaction to make salt

Metal, solid, left hand side of Periodic table, 11 protons,

Electronic structure = 2, 8, 1

Non - metal, gas, right hand side of Periodic table, 17 protons,

Electronic structure = 2, 8, 7

m3

• Any element from left hand side of table reacts with element from right

• 1 use of periodic table – predict reactions

What are ions?

K

Al P SSiMgNa ArCl

Be N OB CLi NeF

reactive gases

reactive metals

Elements

• Elements are the simplest substances. There are about 100 different elements N

S

OC

Fe

K

NN

N

N

N N

NN

• Each elements has just one particular type of atom that is different to the atoms in any other element

• Even in elements atoms usually join (bond) together.

• In some elements atoms bond to form small simple structures.

• In other elements atoms bond into giant structures with millions of atoms.

Compounds

• Compounds are formed when different elements chemically react together.

• In these reactions different types of atom become chemically bonded.

• Like elements some compounds have small simple structures with just a few atoms bonded together

• Others compounds have large, complex structures containing thousands or even millions of bonded atoms.

OH H

Water – a simple structure

DNA – a large & complex structure

Compounds are not just mixtures

• Reacting is different to just mixing.• The physical and chemical properties of compounds are

veryvery different to their original elements.

Sodium + Chlorine Sodium Chloride

COMPOUNDELEMENTS

Na Cl Cl Na Cl

(silver solid) (green, poison gas)

(Salt, flavours chips)

Mixture – sand and salt, easy to separate (filter)

Copy the Table and fill in the last column.

SiO2Sand

HgMercury

Fe2O3Rust

O2Oxygen

H2OWater

CuSO4Copper sulphate

NiNickel

NaClSodium chloride

Element or compound

FormulaName

compound

element

compound

compound

element

compound

element

compound

Rust consists of

iron combined

with oxygen

Activity

Arranging elements

K

He

Al P SSiMgNa ArCl

Be N OB CLi NeF

When elements are arranged according to their properties what patterns do you see and what element is missing?

reactive metals

unreactive gases

reactive gases

Similar elements go into the same columns.

Hydrogen is an exception. This reactive gas is best positioned above the reactive metals.

Hhydrogen is a special case

The periodic table

Arranging all the elements by atomic number and properties led to the creation of…

the periodic table

H He

Fr Ra Rf Db Sg Bh Hs Mt ? ?Ac ?

K Ca Ga Ge As Se KrSc Ti V Cr Mn Fe Co Ni Cu Zn Br

Cs Ba Tl Pb Bi Po RnHf Ta W Re Os Ir Au HgLa Pt At

Na Mg Al Si P S ArCl

Li Be B C N O NeF

Rb Sr In Sn Sb Te XeY Zr Nb Mo Tc Ru Pd Ag CdRh I

Columns of elements

H

Li

Na

K

Rb

Cs

Fr

Be

Mg

Ca

Sr

Ba

Ra

Ga

In

Tl

Al

B

Ge

Sn

Pb

Si

C

Sb

Bi

P

N

As Se

Te

Po

O

S

He

Kr

Ne

Ar

Rn

Xe

Sc Ti V Cr Mn Fe Co Ni Cu Zn

Y Zr Nb Mo Tc Ru Pd Ag CdRh

Hf Ta W Re Os Ir Au HgLa Pt

Rf Db Sg Bh Hs Mt ? ?Ac ?

Br

At

Cl

F

I

What are columns of elements called?

765432

GroupsGroups

1 0Group number

transition elements

Rows of elements

H He

Li Be N O F NeB C

Na Mg Al P S Cl ArSi

K Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge Se BrCa KrAs

Rb Y Zr Nb Mo Tc Ru Pd Ag Cd In Sn SbSr TeRh I Xe

Cs Ba Hf Ta W Re Os Ir Au Hg Tl Pb Bi PoLa AtPt Rn

Fr Ra Rf Db Sg Bh Hs Mt ? ?Ac ?

PeriodsPeriodsWhat are rows of elements called?

1

2

3

4

5

6

7

Period number

H He

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg

V Cr Mn Fe Co Ni Cu Zn Ga Ge Se BrCa Kr

Y Zr Nb Mo Tc Ru Pd Ag Cd In Sn SbSr TeRh

Ba Hf Ta W Re Os Ir Au Hg Tl Pb Bi PoLa AtPt

Ra Rf Db Sg Bh Hs Mt ? ?Ac ?

Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

B C

As

What is the Group and Period of this element?

Mg

C

Group 2 Group 4Group 7

Cl

K

Group 1MgCClK

Name the position

7654321 0

2

3

4

5

6

7

Period 3Period 2Period 3Period 4

1

H1 He

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg

V Cr Mn Fe Co Ni Cu Zn Ga Ge Se BrCa Kr

Y Zr Nb Mo Tc Ru Pd Ag Cd In Sn SbSr TeRh

Ba Hf Ta W Re Os Ir Au Hg Tl Pb Bi PoLa AtPt

Ra Rf Db Sg Bh Hs Mt ? ?Ac ?

Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

B C

As

3

11

19

37

55

87

4

21 22

12

23 24 25 26 27 28 29 30 31 32 34 3520 36

39 40 41 42 43 44 46 47 48 49 50 5138 5245

56 72 73 74 75 76 77 79 80 81 82 83 8457 8578

88 104105106107108109 11111289 110

13 15

7 8

16 17

9 10

18

86

53

14

54

2

5 6

33

Missing elements!

In this periodic table the symbols are replaced by atomic numbers. Some of the numbers are missing – where?

Two more periods of elements fit here but are only shown on some periodic tables. These are called the lanthanides and actinides.

H

Li

Na

K

Rb

Cs

Fr

Be

Sc Ti

Mg

V Cr Mn Fe Co Ni Cu Zn Ga Ge Se BrCa Kr

Y Zr Nb Mo Tc Ru Pd Ag Cd In Sn SbSr TeRh

Ba Hf Ta W Re Os Ir Au Hg Tl Pb Bi PoLa AtPt

Ra Rf Db Sg Bh Hs Mt ? ?Ac ?

Al P

N O

S Cl

F Ne

Ar

Rn

I

Si

Xe

He

B C

As

Periodic table

Stick in book and label groups, periods

1+ ion ProtonsElectrons

1- ion ProtonsElectrons

Ions and Electron Structures

• Ions are atoms that have either extra electrons added or electrons removed.

Atoms ProtonsElectrons

Lose 1 electron Gain 1 electron

So in ions the number of

electrons no longer equals the

number

of protons

Title - Ions

• These are ions formed by the atom losinglosing one or more electrons.

• They are called cationscations. This is because during electrolysis they move towards the cathode. (Or because they are “pussytive”!).

• The charge on the ions is equal to the number of equal to the number of electrons that the atom has lostelectrons that the atom has lost.

• In equations the charge is usually shown above and to the right of the symbol. (E.g. Mg2+ ).

Positive Ions

Lost 1 e- +

Lost 2 e- 2+

Lost 3 e- 3+

It is nearly always metal

atoms that lose

electrons

Ions usually have

OUTER electron

shells that are either completely full or else

empty

Na Bye!

The Electrons in a Sodium IonIn the sodium atomatomAtomic number = number of protons = 11 Number of electrons = 11

Electron arrangement: 2.8.1 (Incomplete Shell)

Na+

Electron lost

Electron arrangement: 2.8 (Full Shells)

23

Na11

Mg

The Electrons in a Magnesium IonIn the magnesium atomatomAtomic number = number of protons = 12 Number of electrons = 12

Electron arrangement = 2.8.2 (Incomplete shell)

Mg2+

Electron arrangement 2.8 (Full Shells)

Bye!

Bye!

2 electrons lost

24

Mg12

The Lithium Ion

Li

3

2

1

1st Shell = 2: full

2nd Shell = 1: not full

2.1

1

•How many electrons?

•How many electrons in the first shell?

•How many electrons in the second shell?

What electron arrangement?

How many electrons to lose?

New electron arrangement? Include a diagram

2.(0)

Bye!Li+

7

Li3

Activity

The Boron Ion

B

5

2

3

1st Shell = 2: full

2nd Shell = 3: not full

2.3

3

•How many electrons?

•How many electrons in the first shell?

•How many electrons in the second shell?

What electron arrangement?

How many electrons to lose?

New electron arrangement? 2.(0)

Bye!

Bye!

Bye!

B3+

11

B5

Activity

• Write/draw a summary of what you now know about positive ions

• Lose or gain electrons?• Go to + or – in electrolysis?• The charge of an ion is less, equal

or more than the number of electrons lost?

• How are they written? • Draw structure of

Mg ion (Mg = 12 electrons)

Lose electron

-, Cations, “pussytive”

Equal

Na+, Mg2+

What have I learnt?

m5

Mg2+

• These are ions formed by the atom gaininggaining one or more electrons.

• They are called anionsanions. This is because during electrolysis they move towards the anode.

• The charge on the ions is equal to the number of equal to the number of electrons that the atom has gainedelectrons that the atom has gained.

• In equations the charge is usually shown above and to the right of the symbol. (E.g.. O2- ).

Negative Ions.

Gain 1 e- -

Gain 2 e- 2-

Gain 3 e- 3-

It is nearly always

non-metal atoms that

gain electrons

Ions usually have

OUTER electron

shells that are either completely full or else

empty

The Electrons in a Sulphide Ion.In the sulphur atomatomAtomic number = number of protons = 16 Number of electrons = 16

Electron arrangement: 2.8.6 (incomplete shell)

Electron arrangement 2.8.8 (Full shells)

2 electrons gained

S S2-

32

S16

The Electrons in a Fluoride Ion.

In the fluorine atomatomAtomic number = number of protons = 9 Number of electrons = 9

Electron arrangement: 2.8.7 (incomplete shell)

Electron arrangement 2.8.8 (Full shells)

1 electron gained

F F-

19

F9

The Oxide Ion16

O8

O

8

2

6

1st Shell = 2: full

2nd Shell = 6: not full

2.6

2

•How many electrons?

•How many electrons in the first shell?

•How many electrons in the second shell?

What electron arrangement?

How many electrons to gain?

New electron arrangement? 2.8

O2-

Activity

• Write/draw a summary of what you now know about negative ions

• Lose or gain electrons?• Go to + or – in electrolysis?• The charge of an ion is less, equal

or more than the number of electrons lost?

• How are they written? • Draw structure of

O ion(O 8 electrons)

Gain electron

+, anions

Equal

Cl-, O2-

What have I learnt?

m5

O2-

x

x

Sodium with Chlorine• Write a word equation for the

reaction• Write a balanced symbol equation• Label equation with group for

elements• Label equation with properties• Draw the sodium and chloride ion

structure

What have I learnt?

The End