group ii elements - alkaline metals

7/29/2019 Group II Elements - Alkaline Metals

1/49


2/49

Location on the periodic table.


3/49

Physical Properties.

They are harder and denser than sodium andpotassium, and have higher melting points.

(this is due to the presence of two valent

electrons in the outermost shell of each atom,which results in stronger metallic bonding

than group 1)


4/49

The atomic and ionic radius increases as you

go down the group. The ionic radii are much smaller than the

atomic radii.

(this is because the atom contains twoelectrons in its outermost shell, which areremoved to form the ion. So the remainingelectrons are closer to the nucleus, and the

increased nuclear charge attracts theelectrons closer to the nucleus, thusdecreasing the size of the ion.)


5/49

Chemical Properties. Reactions with oxygen and chlorine are vigorous.

2Mg(s) + O2(g)

2MgO(s) Ca(s) + Cl2(g)

CaCl2(s) All the metals except beryllium form oxides in air.

Barium is so reactive, its stored in oil.

All the metals except beryllium reduce water and dilute acids

to hydrogen. Mg(s) + 2H+(aq)Mg(aq) + H2(g) Magnesium reacts slowly with water unless the water is

boiling, but calcium reacts rapidly even at room temperature,

and forms a cloudy white suspension ofsparingly soluble

calcium hydroxide. Calcium, strontium and barium reduce hydrogen gas when

heated, forming a hydride. Ca(s) + H2(g)CaH2(s)

The hot metals also reduce nitrogen gas and form nitrides

3Mg(s) + N2(g)Mg3N2(s)


6/49

Magnesium can reduce, and burn in, carbon

dioxide: 2Mg(s) + CO2(g)2MgO(s) + C(s)

Calcium, strontium and barium oxides react

with water to form hydroxides

CaO(s) + H2O(l)Ca(OH)2(s)

(Calcium hydroxide is known as slaked lime. It is

sparingly soluble in water and the mildly alkaline

solution is known as lime water which is used to

test for the acidic gas carbon dioxide.)


7/49


8/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Beryllium DOES NOT add color tothe flame upon burning.

The colour of the flame remains

the original one or has a whitishcolour as that of Magnesium.

Therefore Beryllium does not

have an accurate flame test colour.


9/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Magnesium burns with asparkling white flame

This flame is very bright and can

be blinding

It is used in special Magnesium

lights.

2Mg + O2 = 2MgO


10/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Calcium burns with a strongbrick-red

2Ca + O2 = 2CaO


11/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Strontium burns with a red-crimson flame.

2Sr + O2 = 2SrO


12/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Barium burns with a pale/apple

green. 2Ba + O2 = 2BaO

Fire cracker with Barium


13/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Radium burns with a purple-redflame.

However it is a very violent

combustion, therefore a GeigerMuller tube is used.

The Geiger Muller tube or Geiger

counter detects the radiation toidentify the element.


14/49

Sources

http://en.wikipedia.org/wiki/Flame_test

http://en.wikipedia.org/wiki/Alkaline_earth_

metal

http://webmineral.com/help/FlameTest.shtml

http://www.rsc.org/chemsoc/visualelements/

pages/data/intro_groupii_data.html

Videos from Youtube (Multiple Search Keys)
http://en.wikipedia.org/wiki/Flame_testhttp://en.wikipedia.org/wiki/Alkaline_earth_metalhttp://en.wikipedia.org/wiki/Alkaline_earth_metalhttp://webmineral.com/help/FlameTest.shtmlhttp://www.rsc.org/chemsoc/visualelements/pages/data/intro_groupii_data.htmlhttp://www.rsc.org/chemsoc/visualelements/pages/data/intro_groupii_data.htmlhttp://www.rsc.org/chemsoc/visualelements/pages/data/intro_groupii_data.htmlhttp://www.rsc.org/chemsoc/visualelements/pages/data/intro_groupii_data.htmlhttp://webmineral.com/help/FlameTest.shtmlhttp://en.wikipedia.org/wiki/Alkaline_earth_metalhttp://en.wikipedia.org/wiki/Alkaline_earth_metalhttp://en.wikipedia.org/wiki/Flame_test


15/49


16/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Reactivity

Trend


17/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Reactivity

Trend

I

N

C

R

EA

S

I

N

G


18/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Reactivity

Trend

I

N

C

R

EA

S

I

N

G

Least Reactive


19/49

Be

Beryllium

MgMagnesium

Ca

Calcium

Sr

Strontium

Ba

Barium

Ra

Radium

Reactivity

Trend

I

N

C

R

EA

S

I

N

G

Least Reactive

Most Reactive


20/49


21/49

Magnesium Calcium Strontium Barium


22/49

Sources

http://en.wikipedia.org/wiki/Alkaline_earth_metal

http://en.wikibooks.org/wiki/General_Chemistry/

Chemistries_of_Various_Elements/Group_2 http://www.chemguide.co.uk/inorganic/group2/r

eacth2o.html

http://wiki.answers.com/Q/What_is_the_trend_

of_reactivity_of_group_2_elements

Videos from Youtube (Multiple Search Keys)
http://en.wikipedia.org/wiki/Alkaline_earth_metalhttp://en.wikipedia.org/wiki/Alkaline_earth_metalhttp://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_2http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_2http://www.chemguide.co.uk/inorganic/group2/reacth2o.htmlhttp://www.chemguide.co.uk/inorganic/group2/reacth2o.htmlhttp://wiki.answers.com/Q/What_is_the_trend_of_reactivity_of_group_2_elementshttp://wiki.answers.com/Q/What_is_the_trend_of_reactivity_of_group_2_elementshttp://wiki.answers.com/Q/What_is_the_trend_of_reactivity_of_group_2_elementshttp://wiki.answers.com/Q/What_is_the_trend_of_reactivity_of_group_2_elementshttp://www.chemguide.co.uk/inorganic/group2/reacth2o.htmlhttp://www.chemguide.co.uk/inorganic/group2/reacth2o.htmlhttp://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_2http://en.wikibooks.org/wiki/General_Chemistry/Chemistries_of_Various_Elements/Group_2http://en.wikipedia.org/wiki/Alkaline_earth_metalhttp://en.wikipedia.org/wiki/Alkaline_earth_metal


23/49


24/49

Beryllium

It is used in small amounts to make copper

beryllium alloy that are very strong and hard.

These alloys are used to make hand tools to

be used in environment where sparking isconsidered a fire hazard. It is also used in

making small precision bearings. Alloys of

nickel and beryllium are used for makingcomponents that need to withstand very high

temperatures.


25/49

Magnesium

Magnesium is an element important for all

living beings, as a constituent of chlorophyll

responsible for photo-synthesis in plants.

Magnesium, being light and strong metal, itsalloy with aluminum and zinc finds many uses

in construction and in manufacture of

airplane.


26/49

Calcium

It is an important nutrient for us forming a majorpercentage of our bones and teeth. Its compoundssuch as limestone and gypsum are used as buildingmaterials since ancient times, and continue to be used

today also directly or as raw material for making otherconstruction material. Marble used as decorative stonein construction is also a compound of calcium. Lime isused for in many industrial processes such as steel

refining, paper making, food, cosmetic,pharmaceutical, toothpaste, chewing gum, andvitamins. It is also used for treating industrial waste.


27/49

Strontium

Compounds are widely used in fireworks and

flares for the red color they produce when

burnt. Strontium carbonate is used as a glass

additive. Strontium hydroxide is used forrefining beet sugar.


28/49

Barium

Barium sulfate, in well-drilling operations as a

lubricating mud. A form of barium sulfate

called barium meal is used in medical field to

examine functioning of digestive process ofpatients through X-ray.


29/49

Organic Chemistry

The alkaline earth metals are known to form

organometallic compunds.Of these,

organomagnesium compounds, usually in the

form of Grignard reagents are widely used inOrganic Chemistry. Other important

compounds formed are Organoberyllium,

Organocalcium, Organostrontium,Organobarium and Organoradium.


30/49


31/49

Limestone Cycle

Limestone Starts off as Calcium Carbonate , when heated thecalcium carbonate becomes Calcium Oxide (this is also known assolid Quicklime) + Carbon Dioxide, the Calcium Oxide then reactswith water to produce Calcium Hydroxide and then when morewater is added then filtered it becomes Calcium Hydroxide Solution,C02 is then added to form Calcium Carbonate again.

1. Calcium Carbonate ---> Calcium Oxide(s) + Carbon Dioxide(g).CaCO3(s) + heat --->CaO(s) + CO2(g).

2. Calcium Oxide(s) + Water(l) ---> Calcium Hydroxide(s)2CaO(s) + H2O(l) ---> 2Ca(OH)2(s).

3. Calcium Hydroxide(aq) + Carbon Dioxide (g) ---> CalciumCarbonate(s) + Water (l)

2Ca(OH)2(aq) + 2CO2(g) ---> 2CaCO3(s) (suspension) + 2H2O(l)


32/49

The Limestone Cycle


33/49


34/49

Q1. In the olden days, the photographers flash

bulb gave out a shot of sparkling bright- white

light to light up the subject. What Group 2aelement could have possibly been used in the

bulb?

a. Barium

b. Calcium

c. Magnesiumd. Strontium

DO NOT USE ARROW KEYS TO PROCEED TO NEXT SLIDE


35/49

Next

QuestionGo back to

Question



36/49

Next

QuestionGo back to

Question



37/49

Q2. A boy lights up a firecracker made with

metals from Group 2a of the periodic table.

The firecracker bursts with white and greensparks. What elements could the firecracker

contain?

a. Magnesium and Strontium

b. Strontium and Calcium

c. Magnesium and Calcium

d. Barium and Magnesium



38/49

Next

QuestionGo back to

Question



39/49

Next

QuestionGo back to

Question



40/49

Q3. Select the correct order of reactivity.(Increasing)

a. Barium, Magnesium, Calcium, Strontium,Beryllium, Radium

b. Beryllium, Magnesium, Calcium, Strontium,

Barium, Radium

c. Magnesium, Beryllium, Calcium, Strontium,Barium, Radium

d. Radium, Barium, Strontium, Calcium,Magnesium, Beryllium



41/49

Next

QuestionGo back to

Question



42/49

Next

QuestionGo back to

Question



43/49

Q4. This element combines with other metals to

form an alloy which is used to make tools to

be used in an environment where sparking isconsidered a fire hazard. What Group 2A

element is this?

a. Beryllium

b. Barium

c. Calciumd. Strontium



44/49

Next

QuestionGo back to

Question



45/49

Next

QuestionGo back to

Question


Q4 D t i h th T F l


46/49

Q4. Determine whether True or False:

1. Limestone Starts off as Calcium Carbonate

2. Calcium Carbonate is also known asQuicklime

3. Beryllium and Magnesium can both formoxides in air

a. True, False, True

b. True, False, False

c. True, True, False

d. False, Flase, True



47/49

Next

QuestionGo back to

Question



48/49

Next

QuestionGo back to

Question



49/49

group ii elements - alkaline metals

Documents