Lewis Structures and Valence Electrons

The video tutorial explains how to write the Lewis structure for BrCl2-. It begins by counting the valence electrons of bromine and chlorine, considering the extra electron due to the negative charge. Bromine is placed in the center with chlorine atoms on either side. Electrons are distributed to form bonds and complete the octet, with bromine having an expanded octet. Formal charges are calculated to ensure stability, and the structure is finalized with brackets and a negative charge to indicate it is an ion.

How many total valence electrons are there in BrCl2-?

• 18

• 24

• 22

• 20

Which atom is placed at the center in the Lewis structure of BrCl2-?

• Bromine

• Chlorine

• Hydrogen

• Oxygen

What is the purpose of placing electrons between atoms in a Lewis structure?

• To show the chemical bond

• To indicate the charge

• To represent the atomic number

• To display the atomic mass

How many valence electrons are used after completing the octet for bromine and chlorine?

• 16

• 18

• 20

• 22

What allows bromine to have more than eight electrons in its valence shell?

• Its high electronegativity

• Its ability to form double bonds

• Its small size

• Its expanded octet capability

Why is the extra electron pair placed on bromine instead of chlorine?

• Bromine is more electronegative

• Chlorine cannot form bonds

• Chlorine has a higher atomic number

• Bromine can have an expanded octet

What is the formal charge on bromine in the BrCl2- structure?

• -2

• -1

• 0

• +1

What is the formal charge on each chlorine atom in the BrCl2- structure?

• +1

• -2

• 0

• -1

What is the significance of placing brackets around the Lewis structure of BrCl2-?

• To indicate it is a molecule

• To show it is an ion

• To denote the number of bonds

• To highlight the central atom

What charge is placed on the BrCl2- structure to indicate its ionic nature?

• +1

• 0

• -1

• -2