A metal is a chemical element that is a good conductor of both electricity and heat and forms cation and ionic bonds with non-metal.
Two properties of metals and non-metals:
Metals - They are malleable
-They are lustrous
Non-metals - they are poor conductor of heat and electricity compared to metals.
- they have high electronegativity
Three physical properties of metals:
1)Metals are solid at normal temperature except mercury
2)Metal transform to liquid from solid and to gas from liquid at definite temperatures which are high for most metals except mercury, sodium and potassium.
3)Metal reflects equally nearly all visible electromagnetic waves.
Tuesday, October 26, 2010
Monday, October 25, 2010
Waves
A wave is a disturbance that travels through time and space usually by the transfer of energy.There are different types of waves.
1)Longitudinal waves
2)Transverse waves
When the particles of the waves are displaced parallel to the direction of the propagation of the wave, it is called the longitudinal wave.
When the particles of the waves are displaced perpendicular to the propagation of the wave, it is called transverse wave.
You can also see the link given here for the progressive waves.
Next time we will learn about the properties of waves.
1)Longitudinal waves
2)Transverse waves
When the particles of the waves are displaced parallel to the direction of the propagation of the wave, it is called the longitudinal wave.
When the particles of the waves are displaced perpendicular to the propagation of the wave, it is called transverse wave.
You can also see the link given here for the progressive waves.
Next time we will learn about the properties of waves.
Sunday, October 24, 2010
Molecular formula of compounds
A compound is a chemical substance formed from two or more elements which can be separated into its constituent elements.
Now let's learn what is molecular formula of compounds.
Molecular formula of compounds shows the constituent elements of the compound with their symbols and number of atoms on each element contained in the compound.
We will learn how to represent some compounds in their molecular formula.
Lead carbonate - its molecular formulae is 2PbCO3.Pb(OH)2
Sodium Chloride - its molecular formula is NaCl
Carbon dioxide - CO2
Molecular formulas go one step beyond the empirical formula in that they express not only the correct ratio but the correct number of atoms in the molecule.
Now let's learn what is molecular formula of compounds.
Molecular formula of compounds shows the constituent elements of the compound with their symbols and number of atoms on each element contained in the compound.
We will learn how to represent some compounds in their molecular formula.
Lead carbonate - its molecular formulae is 2PbCO3.Pb(OH)2
Sodium Chloride - its molecular formula is NaCl
Carbon dioxide - CO2
Molecular formulas go one step beyond the empirical formula in that they express not only the correct ratio but the correct number of atoms in the molecule.
Monosaccharide structures
Carbohydrates are made up of carbon, hydrogen and oxygen.They are the most abundant source of energy for all living organism.Some of the other functions of carbohydrates include participation in cell growth, it also acts as chief structural material for cell walls in plants.
In their basic form, carbohydrates are simple sugars.These sugars are classified according to the number of carbons.
No.of carbons Category names Examples.
4 Tetrose erythrose
5 pentose arabinose
6 hexose allose
7 heptose sedoheptulose
The structures of carbohydrates are shown below:
D-erythrose D-rebose D-allose D-sedoheptulose
In their basic form, carbohydrates are simple sugars.These sugars are classified according to the number of carbons.
No.of carbons Category names Examples.
4 Tetrose erythrose
5 pentose arabinose
6 hexose allose
7 heptose sedoheptulose
The structures of carbohydrates are shown below:
D-erythrose D-rebose D-allose D-sedoheptulose
Friday, October 22, 2010
Food chain
Food chain of animals is defined as the transfer of food energy from one organism to another organism in an ecology.A food chain of animals starts with producers, then herbivores and ends with carnivores.
For example, herbs and plants are producers, grass-shoppers and cow are herbivores and tigers and wolves are carnivores.
A food web is a graphical representation of food chain system.An example of food web diagram is shown below:
You will find food chain for different animals according to their ecosystem.Animals can be terrestrial or aquatic.
For example, herbs and plants are producers, grass-shoppers and cow are herbivores and tigers and wolves are carnivores.
A food web is a graphical representation of food chain system.An example of food web diagram is shown below:
Pollution
Pollution has become one of the major issues nowadays.Pollution means undesirable state of natural environment being contaminated with harmful substances as a result of human activities.
Polythene pollution is one of the main problem which is created by widespread use of poly-bags and bottles.Polythene is non-bio-degradable.It is one of the causes of floods due to blockage of water.Because of industries and factories, water is being polluted leading to many health hazards.You will find many facts about water pollution in newspapers and magazines.Not only water, air is also polluted with unwanted chemicals in the form of solid particles or air.Carbon monoxide is one of the example of poisonous gas.
Steps have been taken to reduce the use of polythene by replacing it with recyclable paper bags.Limits have been given to different countries by International union in the release of carbon by industries.
Polythene pollution is one of the main problem which is created by widespread use of poly-bags and bottles.Polythene is non-bio-degradable.It is one of the causes of floods due to blockage of water.Because of industries and factories, water is being polluted leading to many health hazards.You will find many facts about water pollution in newspapers and magazines.Not only water, air is also polluted with unwanted chemicals in the form of solid particles or air.Carbon monoxide is one of the example of poisonous gas.
Steps have been taken to reduce the use of polythene by replacing it with recyclable paper bags.Limits have been given to different countries by International union in the release of carbon by industries.
Periodic table
The periodic table of elements is a table that provides information of elements in a systematic manner.It gives the information about the names and properties of elements.
The periodic table is divided into groups and periods.A group is a vertical column in a periodic table.There are 18 groups.The elements in a group have similar electronic configuration of the outermost shell.Electronic configuration of elements is the arrangement of electrons in the shells of an atom.A period is the horizontal row in the periodic table.Elements in a period have the same number of electron shells.
Elements of the Halogen family which are in group 17 in the periodic table is the most reactive elements whereas group 8A consists of elements which are considered as the least reactive elements.
The periodic table is divided into groups and periods.A group is a vertical column in a periodic table.There are 18 groups.The elements in a group have similar electronic configuration of the outermost shell.Electronic configuration of elements is the arrangement of electrons in the shells of an atom.A period is the horizontal row in the periodic table.Elements in a period have the same number of electron shells.
Elements of the Halogen family which are in group 17 in the periodic table is the most reactive elements whereas group 8A consists of elements which are considered as the least reactive elements.
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