Question

What are called valence electrons?

Answer 1

Hint : Inside every element, there are shells present surrounding the nucleus. And every shell contains electrons embedded in it. The total numbers of electrons present in the outermost shell are the valence electrons. It is easy to determine the valence electrons of an atom from the periodic table.

Complete Step By Step Answer:
Electrons present in the outermost orbit of an atom are called valence electrons. These electrons can participate in the formation of chemical bonds. They are all arranged in different orbitals or shells and are mostly negatively charged particles. The electrons present in the inner shell are core electrons. Valence electrons are also responsible for the emission spectra and the chemical properties of an element. The presence of valence electrons can determine the element's chemical properties and whether it may bond with other elements: For the main group element, a valence electron can only be in the outermost electron shell.
The valence electrons contain more energy than the electrons present in inner orbits, so they are part of most chemical reactions. The number of valence electrons of an atom can be obtained from the periodic table as the group number of any element is its number of valence electrons. Atoms mostly prefer to have a filled valence shell of electrons because it makes them more stable. An atom consisting of a closed shell of valence electrons will usually be chemically inert. Valence electrons also determine the electrical conductivity of an element. Depending on this nature of elements can be metal, non-metal, or a metalloid.

Note :
Valency is different from valence electrons. Valence electrons are outermost electrons that take part in bond formation or the electrons in the outermost shell whereas valency is the number of bonds the atom can form around it or the number of electrons required for full outermost energy level.