Atom
Around 500 BC ago Indian philosopher experiments on rice , he called it Padarth they break rice into very small tiny particles until they don’t break it then they give them name of Parmanu. During that time Greeks Philosopher Democritus, and Leucippus also work on this.
“All matter is composed of small indivisible particles called Atom.”
- Atom are the building blocks of the matter.
- Atom are the smallest particles of elements which may or may not be capable in free state. Atom are always take a part in chemical reaction .
- Atom exists in combination same atom of elements or different atoms of elements for example O2, CO2,
- The atom of few elements called Nobel gases, which are chemically unreactive and exist in free state. For example helium, Neon, Aragon, Krypton etc.
- Atom of the few elements are very reactive and do not exist in free state.
- Atom of different elements are different in mass, size, and chemical properties.
- Atom consists three sub atomic particles are protons, neutron, and electrons.
For example if we take small sand grains and we closer look at a sand grains under scanning tunneling, microscope (STM) . We can see that every small grain of sand consists of millions of particles which are miniscule in nature.These particles are called atom.
- Atom is made up of three types of components Protons, neutron and electrons
- Atom has central nucleus with protons and neutron init.
- Protons are positively charge and neutron have no charge that is neutral.
- So nucleus is positively charge. Protons and neutron collectively called nucleon.
- Electrons are negatively charge and are located around Central Nucleus the Nucleus. Or outermost region of atom are called electrons shell.
- Atom has same number of negatively charge electrons as it has positively charge protons in the nucleus.
Therefore atom are electrically Neutral.
Size of the atom:
- Atom are very small in size.
- Atom are consider to be spherical.
- The size of atom indicate by radius which is called atomic radius.
- Atomic radius is measured in nanometre that is 1nm = 10-9.nm
- For example Hydrogen atom are most smallest Of all having a atomic radius of 0.037nm
- Atoms are very small that is we can not see them under most powerful optical microscope.
- It is only recently that a highly sophisticated microscope known as scanning tunneling microscope (STM) has been delivered which has made it possible to take photographs of atom.
Sr. No |
Example | Radii (In m) |
1. |
Hydrogen |
10-10
|
2. | Water molecule |
10-9
|
3. |
Molecule of haemoglobin | 10-8
|
4. | Sand grains |
10-4
|
Question Answer:
1) What is atom?
Answer: All matter is composed of small indivisible particles called Atom.”
Or
Atom are the building blocks of the matter.
2) Write down a properties of atom?
Answer:• Atom are the building blocks of the matter.
- Atom are the smallest particles of elements which may or may not be capable in free state. Atom are always take a part in chemical reaction
- Atom exists in combination same atom of elements or different atoms of elements for example O2, CO2,
- The atom of few elements called Nobel gases, which are chemically unreactive and exist in free state. For example helium, Neon, Aragon, Krypton etc.
- Atom of the few elements are very reactive and do not exist in free state.
- Atom of different elements are different in mass, size, and chemical properties.
- Atom consists three sub atomic particles are protons, neutron, and electrons.
3) Explain Size of the atom?
Answer: • Atom are very small in size.
- Atom are consider to be spherical.
- The size of atom indicate by radius which is called atomic radius.
- Atomic radius is measured in nanometre that is 1nm = 10-9 .nm
- For example Hydrogen atom are most smallest Of all having a atomic radius of 0.037nm.
- Atoms are very small that is we can not see them under most powerful optical microscope.
- It is only recently that a highly sophisticated microscope known as scanning tunneling microscope (STM) has been delivered which has made it possible to take photographs of atom.