find the valancy and valance electron from atomic no 1 to 20.
Answers
Explanation:
Electrons in an atom are arranged in different orbitals (shells) represented as K, L, M, N, and so on. The electrons present in the outermost shell/orbit of an atom are called valence electrons. The valence electrons take part in any chemical reaction because the outermost orbit usually contains more energy than the electrons present in other orbits.
According to the Bohr-bury scheme, the outermost orbit of an atom will have a maximum of 8 electrons. However, if the outermost orbit is completely filled then very little to no chemical activity is observed in the particular element. Their combining capacity becomes negligible or zero.
Understand the concept of Sub-atomic Particles here in detail.
This is why noble gases are least reactive because their outermost orbit is completely filled. However, the reactivity of other elements depends upon their capacity to gain noble gas configuration. It will also help to determine the valency of an atom.
Element Symbol Atomic Number Valency
Hydrogen H 1 1
Helium He 2 0
Lithium Li 3 1
Beryllium Be 4 2
Boron B 5 3
Carbon C 6 4
Nitrogen N 7 3
Oxygen O 8 2
Fluorine F 9 1
Neon Ne 10 0
Sodium Na 11 1
Magnesium Mg 12 2
Aluminum Al 13 3
Silicon Si 14 4
Phosphorus P 15 3
Sulphur S 16 2
Chlorine Cl 17 1
Argon Ar 18 0
Potassium K 19 1
Calcium Ca 20 2