Question

Define valence shell and valence electrons?

Answer 1

Valence shell:

• The outermost shell or orbital of an atom is called its valence shell.
• The electrons in these shells take part in bonding with other atoms.
• It may be fully filled or half-filled.
• For example, the atomic number of magnesium (Mg) is 12 and its electronic configuration is 1s²2s²2p⁶3s². So, here 3s is the valence shell of the magnesium atom.

Valence electrons:

• The total number of electrons present in the outermost shell are called valence electrons.
• The valence electrons are part of most the chemical reactions because they contain more energy compared to the electrons present in inner orbits.
• For example, the atomic number of magnesium (Mg) is 12 and its electronic configuration is 1s²2s²2p⁶3s². So, here the number of valence electrons is 2.