Sulfuric acid and sulfates

9 «В» класс

КГУ ОШ № 160

г. Алматы

«Metals 1, 2, 13 groups elements and their compounds». Teacher: Irina Sannikova

Lesson plan:

• Let s start
• You will
• Terminology
• Alkali metals and their compounds
• Alkaline earth metals and their compounds
• Aluminum and its compounds
• True and false
• Test

You will:

• know which metals are called alkali metals;
• know properties of alkali metals according to their atomic structure;
• know which metals are called alkaline earth metals;
• be able to compare properties of first and second groups;
• know properties of aluminum according to its atomic structure;
• know amphoteric properties of aluminum and its compounds.

TERMINOLOGY

alkali metals - щелочные металлы

table salt NaCl – столовая (поваренная)соль

nutrition – питание

caustic soda NaOH – каустическая сода

baking soda NaHCO3 – пищевая сода

potash K2CO3 – поташ

alkaline earth metals – щелочноземельные металлы

lime CaO – известь

limestone CaCO3 –известняк

gypsum CaSO4 * 2H2O –гипс

bauxide Al2O3 * nH2O – боксит

amphoteric - амфотерный

Alkali metals and their compounds.

Alkali metals: lithium Li, sodium Na, potassium K, rubidium Rb, cesium Cs and francium Fr .

The name «alkali» comes from the Arabic word «algaly» meaning basic.

Sodium comes from the word «soda» and potassium comes from the word «potash».

Structure of atoms

Alkali metals have one valence electron and form +1 charged ions.

The activity of metals increases from top to bottom and Francium is expected to be the most active metal in the periodic table.

Alkali metals are the most active metals.

Physical properties.

Cs Cesium

Li Lithium

Alkali metals are silvery-white, they are very soft.

Alkali metals are the most active metals, so they need to be stored under oil or kerosene.

K Potassium

Ru Rubidium

Na Sodium

Chemical properties

Reaction with water.

Alkali metals react with water and produce bases:

2Na + 2H 2 O = 2NaOH + H 2

2Li + 2H 2 O = 2LiOH + H 2

Reaction with acids:

2Na + 2HCl = 2NaCl + H 2

Compounds of alkali metals can be identified by use of the flame test:

Lithium Li+ red Sodium Na+ yellow

Potassium K+ lilac Rubidium Rb+ red-violet

Cesium Cs+ blue

Sodium Na +

Lithium Li+

Potassium K+

Alkaline earth metals.

The metals in 2-nd group are called alkaline earth metals.

This group includes beryllium Be, magnesium Mg, calcium Ca,

strontium Sr,

barium Ba and

radium Ra.

Alkaline earth metals have two electrons in their valence shell that occupy the s-orbitals. Therefore, by losing there electrons through a chemical change they gain +2 charge.

Chemical properties:

Alkaline earth metals are second most active metals after alkali metals. The activity of the metals increases from beryllium Be

to barium Ba.

Calcium Ca

Magnesium Mg

Beryllium Be

Alkaline earth metals compounds:

Mg(OH)2 - milk of magnesia. Used in medicine as antacid.

CaSO4 * 2H2O – gypsum. Used in buildings.

CaO – lime. Used in manufacture of cement and casting.

CaC2 – carbide. Used in welding.

CaCO3 – limestone. Used in building.

Sr(NO3)2 – strontium nitrate. Used in fireworks (gives red colour).

Aluminum and its compounds.

+ 13 Al [p13;n14]e13 3s 2 3p 1

Aluminum is an amphoteric metal so that it can react with both acids and bases:

2Al+6HCl=2AlCl3+3H2

2Al+2NaOH+2H2O=2NaAlO2+3H2

Obtaining aluminum.

Application

of aluminum

Al

True/false

1. Sodium ion flame color red.

2. Alkali metals are the most active.

• The most active metal is potassium.
• Caustic soda is part of the soap.
• Carbide is used for welding metals.
• Aluminum is obtained from bauxide.

• F
• T
• F
• T
• T
• T

Test

1. Choose the formula of a caustic soda

A) KOH

B) NaCl

C) NaOH

D) K2CO3

2. Choose the formula of a baking soda

A) Li2CO3

B) KOH

C) CaO

D) NaHCO3

3. Choose the formula of a gypsum

A) CaO

B) CaSO4 * 2 H2O

C) CaC2

D) Mg(OH)2

4. Choose the formula of a limestone

A) CaCO3

B) Na2SO4

C) CaC2

D) BaSO4

5. Choose the formula of a carbide

A) Mg(OH)2

B) CaCO3

C) CaC2

D) Sr(NO3)2

True results:

• C) NaOH
• D) NaHCO3
• B) CaSO4 * 2H2O
• A) CaCO3
• C) CaC2

Results

Good job!

Well done!