Notes on Carbon | Grade 9 > Science > Carbon and Its Compounds | KULLABS.COM

Carbon

  • Note
  • Things to remember
  • Videos
  • Exercise
  • Quiz

Carbon
CarbonAtom

The word ‘carbon’ is derived from the Latin word ‘carbo’ meaning soot or charcoal. Carbon is found in free as well as in combined state. In the free state, it is found nature as diamond, graphite and coal. In the combined state, it is found in compounds like carbon dioxide of air, limestone, chalk etc.

Sources of carbon

  • Carbon dioxide of air.
  • Petroleum matter or natural gases.
  • Minerals and rocks like limestones.
  • Organic compounds like carbohydrate, protein and fat.

Nature of carbon

Carbon is a non-metal. It belongs to group IV A and period 2nd of the periodic table. Its atomic number is 6 and atomic weight is 12. Carbon is the first member of group IV A elements. These six electrons are arranged in different energy levels of a carbon atom as shown below.

Orbit K L
No. of electron 2 4

Carbon has 4 valence electrons. It indicates that carbon can attain a stable configuration like that of inert gases in the following ways:

  • By losing four valence electrons.
  • By gaining four electrons in its valence shell.
  • By sharing its four valence electrons with other atoms.

Physical properties of carbon

Allotropyis the different structural or physical modification of the same element but they have same chemical properties. The different forms of the same element are called allotropes. There are two allotropes of carbon which are given below, Graphite, diamonds and coals are nearly pure form of carbon

  • Crystalline form: diamond and graphite.
  • Amorphous form: coal, charcoal, animal charcoal, coke etc.

Diamond
Diamond

Diamond:

Diamond is considered as thepurest form of carbon which is hardest, transparent and colourless crystalline substance which is naturally formed. It is insoluble in all ordinary solvents.

Uses of diamond

  • It is used as precious gems in jewellery.
  • It is used in cutting and drilling instruments.
  • It is used to make radiation proof windows for spacecraft.
  • It is used to make high quality thermometers.

Graphite
Graphite

Graphite:

Graphite is crystalline allotrope of carbon which is slippery to touch opaque and dark grey solid. It is also called plumbago or black lead.

Uses of graphite

  • It is used as a lubricant.
  • It is used to make lead pencils, electrodes, crucible etc.
  • It is used for coating iron in order to prevent rusting of iron.

Difference between diamond and graphite

Diamond Graphite
It is the hardest substance in the earth. It is soft and slippery.
It is transparent, colourless substance which sparkles. It is opaque, dark grey and shiny substance.
It is a bad conductor of heat and electricity. It is a good conductor of heat and electricity.
Its specific gravity is 3.5. Its specific gravity is 2.2.



  • Carbon is found in free as well as in combine state.
  • The different forms of the carbon due to different physical and chemical modifications are called allotropes.
  • Diamond is considered as purest form of carbon which is hardest, transparent and colourless crystalline substance which is naturally formed.
  • Diamond is considered as purest form of carbon which is hardest, transparent and colourless crystalline substance which is naturally formed.
.

Very Short Questions

The sources of carbon in nature are as follows:

  • Carbon dioxide of air.
  • Petroleum matter and natural gases.
  • Organic compounds like carbohydrates, proteins, fats, etc.
  • Minerals and rocks like limestone.

The property of an element by virtue of which it can exist in more than one form is called allotropy.

Graphite is used as lubricant because it is soft and non-volatile.

Carbon forms covalent compounds because it is non-metal and non-metals form covalent compounds by sharing of electrons.

Diamond is the hardest substance known because each carbon atom in diamond is joined to four other carbon atoms giving rise to a three dimensional rigid and stable structure.

0%
  • Why can't carbon attain octet state by gaining four electrons?

    because carbon has only 4 electrons in its valence shell


    because it creates too much inter electronic repulsion


    because those electrons are strongly held by the nucleus


    because carbon is non-metal


  • Carbon is present in all except?

    Soil
    Salt
    Silk
    Milk
  • Which is true regarding carbon?

    It is non-metallic
    It can exist in different physical form but shows same chemical properties
    It is present in most of the organic life forms
    It can occur in amorphous form
  • How can natural Diamond be separated from artificial Diamond?

    Natural diamond are transparent to X-ray but artificial are not
    Natural diamond has more sparkle than artificial ones
    Natural diamond has more reflective index than artificial ones
    Natural diamond has more density than artificial ones
  • In diamond every carbon is surrounded by ___ carbons

    3
    4
    5
    6
  • In graphite each carbon is surrounded by ___ carbons

    6
    3
    5
    4
  • Which is not a use of diamond?

    Cutting and drilling instruments
    Making spacecrafts radiation proof
    As a surgical tool to remove cataract of eye
    Making high quality electronics
  •  The graphite is a good conductor of heat and electricity because ______.

    each carbon atom in a graphite layer is bonded to other 5 carbon units.


    graphite has sheets of layers of carbons.


    unlike diamond, Graphite is a good conductor of heat and electricity.


    graphite has double bonded electrons which are delocalized.


  • Which is not an use of graphite?

    cutting and drilling instruments
    moderator in nuclear reactions
    manufacturing lead pencils and electrodes
    Lubricant for heavy machinery
  • Which type of bond is in graphite but not in Diamond?

    Electrostatic
    Van Der Waal
    Di-electric
    Co-valent
  • Why can graphite be used as a lubricant?

    Because it has lustrous property
    Because it has covalent bonding which is weak and can be easily overcome
    Because it is very ductile
    Because it has sheets of hexagonal carbon layers which can slide across each other
  • What makes diamond so hard?

    Because diamond has co-valent bond between many carbons
    Because each carbon in diamond forms covalent bond with 4 other carbons and this pattern repeats continuously in all direction
    Because diamond has co-valent bond between many carbons and many hydrogens
    The molecular structure of a diamond makes it hard, as diamonds are comprised of carbon atoms linked closely together in a lattice structure.
  • Which allotrope of carbon doesn't have refractive index?

    Graphite
    lamp Black
    Coal
    Diamond
  • How is charcoal produced?

    By simply burning any organic matter
    By strongly heating wood in air
    By reacting ash and acid and then heating strongly
    By strongly heating organic matter in absence of air
  • What happens when we continuously burn graphite in presence of excess air?

    It will melt
    It will vaporize
    It will produce carbon dioxide
    It will break into small pieces
  • You scored /15


    Take test again

ASK ANY QUESTION ON Carbon


You must login to reply

Forum Time Replies Report
Brijesh Maurya

Write any five physical features of Carbon?


You must login to reply

samir khanal

why carbon contains covalent bond/compound ?


You must login to reply

Lucifer

Is diamond fully transparent?


You must login to reply

What is called carbon?


You must login to reply