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Answer:

Hey Mate, here is ur answer

Explanation:

Valence electrons are electrons that are loosely bound to an atom. Free electrons are completely unbound to any atom. Valence electrons are responsible for the chemical reactions and chemical bonding of atoms. Free electrons take part in heat and electricity conduction of a lattice structure.

To find valence electrons using a period table, first see if your atom is a transitional metal, which are the elements in the middle rectangle of the table. If the atom is outside this block, locate its group number along the top of the table. The ones digit in the group number is the number of valence electrons.

Answer:

An atom can have 1 or more shells the electrons present in the last shell or valence shell are called free electrons or valence electrons

How to count the free electrons or valence electrons:

Step 1: Write the electronic configuration of the atom

Step 2: The number which in the last is the number of free electrons

For example:

1) Sodium

Its electronic configuration is 2,8,1

The last number is 1 so Sodium has 1 valence electron

2) Chlorine

Its electronic configuration is 2,8,7

The last number is 7 so it has 7 valence electrons