Lewis Structures and Valence Electrons

The video tutorial explains how to write the Lewis structure for the BRF4- ion. It begins by counting the valence electrons, noting that bromine and fluorine each have 7 valence electrons, with an extra electron due to the negative charge, totaling 36 electrons. Bromine is placed at the center with four fluorine atoms around it, forming bonds and completing the octets. The remaining electrons are added to bromine, allowing for an expanded octet. The formal charges are calculated, confirming the structure with bromine having a -1 charge. The video concludes with a cleaner representation of the structure.

How many total valence electrons are there in BrF4-?

• 34

• 36

• 38

• 32

Which atom is placed at the center of the BrF4- Lewis structure?

• Fluorine

• Bromine

• Hydrogen

• Oxygen

How many fluorine atoms are arranged around the central bromine atom in BrF4-?

• 5

• 2

• 4

• 3

What is the purpose of adding a pair of electrons between each atom in the Lewis structure?

• To form a chemical bond

• To increase the atomic number

• To decrease the atomic mass

• To change the element

Why does bromine in BrF4- have more than 8 valence electrons?

• It cannot have more than 8 electrons

• Bromine can have an expanded octet

• It loses electrons easily

• It is a noble gas

What is the formal charge on the bromine atom in BrF4-?

• -1

• -2

• 0

• +1

What does the negative charge on BrF4- indicate?

• It has lost an electron

• It has gained an electron

• It is a cation

• It is neutral

What is often used to replace bonds in the Lewis structure for clarity?

• Arrows

• Lines

• Dots

• Numbers

What do the lines in the Lewis structure represent?

• Neutrons

• Protons

• Atomic mass

• Lone pair electrons