Selenium is non metal place between sulphur and tellurium . It is place in chalcogen family
It is found in earth crust rarely . In our body require 14 milligram selenium .
Selenium is toxic in nature . In excess amount it is dangerous to health .it is carcinogenic .
Selenium is photovoltaic ( convert light to electricity ) and it is also conductive
Discovery : selenium is discovered in 1817 by scientist Jon’s Jacob Berzelium
Origin of name :. The name is derived from geek word ‘selene ‘ meaning of this word is moon
Physical properties :
Atomic symbol: selenium is denoted by symbol Se
Atomic number : atomic number of selenium is 34
In selenium 34 proton and 34 electron is present
Atomic weight/ mass: atomic weight of selenium is 78.9 Amu
In selenium 34 proton and 45 neutron is present.
Position: selenium is present in periodic table at 4 period( row ) and 16 column ( group)
Block : it is place in P block
Colour :selenium is silver grey colour element
Nature:. It is present in solid state
Odour : selenium show rotten horseradish odour
Boiling point : boiling point of selenium is 685 0C
Melting point : melting point of selenium is 220 0C
Selenium show 6 stable isotope
74Se: atomic weight of this isotope is 73.9 Amu
In this isotope 34 proton,34 electron 40 neutron is present
It is present 0.8% in nature
76Se: atomic weight of this isotope is 75.9 Amu
In this isotope 34proton,34 electron and 42 neutron is present.
It is present 9.3% in nature
77Se: atomic weight of this isotope is 76.9 Amu
In this isotope 34 proton, 34 electron and 43 neutron is present
It is present 7.6% in nature
78Se: atomic weight of this isotope is 77.9 Amu
In this isotope 34 proton, 34 electron and 44 neutron is present
It is present 23.7% in nature
80Se: atomic weight of this isotope is 79.9 Amu
In this isotope 34 proton,34 electron, 46 neutron is present
It is present 49.6% in nature
82Se : atomic weight of this isotope is 82.9 Amu
In this isotope 34 proton, 34 electron and 48 neutron is present
It is present 8.7% in nature
Chemical properties :
Electronic configuration of selenium is [ Ar] 3d10 4S2 4P4
Electronic configuration in concert of shell is 2,8,18,6
Valency :valency of selenium is 2
In selenium 2 electron is required to complete their octate
Atomic radius : atomic radius of selenium is 103 pm
Reactivity :. Selenium is less reactive element . But it is react with acid .
Selenium is use in anti dandruff shampoo
It is also use to make stainless steel
Selenium is use in photocell and solar sell .
It is use to produce red colour glass.
It is also use as decolourising glass .
Selenium use as catalyst for most of chemical reaction.
Selenium use in T. V. Cameras
It is use to copying documents, letter
It is use in electronics device i.e. Light meter
Question and Answer:
Q1. Define Selenium
Q2. Who discovered Selenium?
Q2. Physical properties of Selenium
Q4. Write Atomic Symbol of Selenium.
Q5. Write the Atomic number of Selenium.
Q6. On which block Selenium element is present?
Q7. What is the color of Selenium?
Q8. What is the Boiling point of Selenium?
Q9. What is the Melting point of Selenium?
Q10. Write the Isotopes of Selenium.
Q11. Show Electronic configuration of Selenium.
Q12. Write Electronic Structure of Selenium.
Q13. What is the Valency of Selenium?
Q14. Write the uses of Selenium element.