Question

using the periodic table, identify the number of valence electrons in an atom of each of the three elements.
element
number of valence electrons

Explanation:

Step1: Determine valence electrons for Li

For main - group elements, the number of valence electrons is equal to the group number (for groups 1 - 2) or the group number minus 10 (for groups 13 - 18). Li is in group 1. So, the number of valence electrons for Li is 1.

Step2: Determine valence electrons for B

B is in group 13. Using the formula (group number - 10), we have \(13 - 10=3\). So, the number of valence electrons for B is 3.

Step3: Determine valence electrons for Cl

Cl is in group 17. Using the formula (group number - 10), we have \(17 - 10 = 7\). So, the number of valence electrons for Cl is 7.

Answer:

Element	Li	B	Cl