In this section you will learn about classification of matter on the basis of atom, element, compound, substance etc.

MOVING IN INNER CONCEPT OF ELECTRICITY

In this you will see classification of matter with its smallest unit.

MATTER

Everything that has mass and occupies space is Matter. We know three states of matter that are solid, liquid and gas. For example gold, wood, ice, water, milk, honey, coffee, air, oxygen, water vapour etc.

Now we can see in chart above, matter is divided (classified) into two categories that are

• Substance &
• Mixture

SUBSTANCE

A substance is simply a pure form of matter. Substance is made up of elements or compounds. Molecules (Atoms can join together – they form bonds together – to make Molecules) of elements or compounds both make substances.

Element are copper (Cu), gold (Au), calcium (Ca), sodium (Na), oxygen(O), carbon (C) etc.

Compounds are water (hydrogen oxide) (H₂O), sodium chloride (common salt or table salt) (NaCl), carbon dioxide gas (CO₂)_, oxygen gas(O2) etc.

Pure substances can be further divided into two sub-categories: elements and compounds.

ELEMENT

Many atoms of same type bonds together to form an element. Elements are the simplest form of matter. There are 118 elements are listed on the periodic table, out of which 94 occur naturally on earth and rest 24 were artificially created .

Examples of elements that are naturally presents: carbon (C), hydrogen (H), oxygen (O), sodium (Na), gold (Au), silver (Ag), calcium (Ca) etc.

Example of elements that are artificially created: technetium Tc(atomic number Z = 43), promethium Pm (Z = 61), neptunium Np (93) etc.

COMPOUND

Compounds, on the other hand, are made up of two or more different elements held together by chemical bonds and functioning as a unit. However, compounds are also pure substances, they differ from elements because compounds can be broke down into simplest elements (the elements that make up the compound). Compounds also have a specific chemical formula like NaCl, or C6H12O6?  If yes, then it is a compound.

Examples of compounds are carbon dioxide (CO2), rust (Fe2O3), water (hydrogen oxide) (H₂O), sodium chloride (common salt or table salt) (NaCl), carbon dioxide gas (CO₂)_, oxygen gas (O2) etc.

MIXTURE

A mixture is made when two or more substances combined, but they are not combined chemically. The components of a mixture can be easily separated, so the components of a mixture can be easily separated and is therefore said to be impure.

Examples of mixtures are

• Honey and tea.
• Milk and chocolate.
• Coffee and sugar.
• Cake ingredients.
• Smog (smoke + fog)
• Mud puddle (dirt + water)
• Air (oxygen + nitrogen + other gasses)
• Atom (nucleus + electrons)
• Cement (sand + water + gravel)
• Dirty snow (water + dirt)
• Ocean water (water + salt)

ATOM

Atom is the smallest unit of matter. An atom composed of three subatomic particles that are electron, proton and neutron. The neutrons and the protons make the center of an atom called nucleus. And the electrons moves around the nucleus in orbits (shell).

Electrons are negatively charged particles, Protons are positive charged particles &Neutron is neutral means no charge is present

Electrons  “–”

Protons  “+”

Neutron  “ ”

Things to be note:

• As we know nucleus composed of proton and neutron, and protons are positively charged and neutron has no charge so overall we can say nucleus is positively charge.
• The strong nuclear force between neutrons and protons stick them together to form a nucleus.
• The negatively charged electrons are orbiting around the nucleus because of the electrostatic force of attraction present between electrons and protons.

If the numbers of electrons are equal to number of protons in an atom then the overall charge of atom is neutral.

And if the numbers of electron are more than the numbers of protons in an atom then the atom is negatively charged.

If the numbers of electron are less than the numbers of protons in an atom then the atom is positively charged.

The charge of proton and electron measures in coulombs, denoted by “C”.

Charge of a electron = – 1.602 × 10^-19 Coulombs (C)

Charge of a proton = + 1.602 × 10^-19 Coulombs (C).

Both the charges are equal in magnitude but have different signs.

THIS IS ALL FOR CLASSIFICATION OF MATTER. NEXT YOU WILL LEARN ORBIT & ENERGY LEVEL OF ORBITS

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