Rules About Molecular Structures

Question 1

coordinate covalent bond

Answer 1

when an atom in a covalent bond contributes both the electrons

they are not indicated in the lewis structure

Question 2

expanded valence

Answer 2

all atoms in the third row and lower can have expanded octet rule because they can have spd orbitals instead of just sp orbitals and the d orbital can hold 10 electrons which is more than 8 electrons so it goes above the octet rule

this is why the central atom is said to have an expanded valence or expanded octet

Question 3

incomplete valence

Answer 3

when the central atom doesn’t obtain the octet rule