Why do expanded valence shells occur?

Why do expanded valence shells occur?

The larger the central atom, the larger the number of electrons which can surround it. Expanded valence shells occur most often when the central atom is bonded to small electronegative atoms, such as F, Cl and O.

What are valence expanded molecule?

There are certain situations in which a stable molecule can form containing atoms of elements that are capable of existing with an expanded valence shell (forming bonds in a way that there are more than 8 electrons in the valence shell). When this occurs the compound is said to exhibit expanded valence.

What happens when a valence shell is full?

This outermost shell is known as the valence shell, and the electrons found in it are called valence electrons. In general, atoms are most stable, least reactive, when their outermost electron shell is full.

Which elements can expand their valence shell?

An atom like phosphorus or sulfur which has more than an octet is said to have expanded its valence shell. This can only occur when the valence shell has enough orbitals to accommodate the extra electrons.

Which element is most likely to form an expanded octet?

Sulfur, phosphorus, silicon, and chlorine are common examples of elements that form an expanded octet. Phosphorus pentachloride (PCl5) and sulfur hexafluoride (SF6) are examples of molecules that deviate from the octet rule by having more than 8 electrons around the central atom.

What rows can expand octet?

Answer: Elements in the 3rd row, 4th row, etc., can have an expanded octet due to d-orbitals. Since Xe is in row 5 it has d-orbitals that can accomodate additional electrons.

Why expanded octet is stable?

Although the energy of empty 3d-orbitals is ordinarily higher than that of the 4s orbital, that difference is small and the additional d orbitals can accommodate more electrons. Therefore, the d orbitals participate in bonding with other atoms and an expanded octet is produced.

What is required for an atom to expand its valence shell?

An atom like phosphorus or sulfur which has more than an octet is said to have expanded its valence shell. This can only occur when the valence shell has enough orbitals to accommodate the extra electrons. For example, in the case of phosphorus, the valence shell has a principal quantum number n = 3.

What is a full valence shell called?

It becomes complete when a shell ends its duplet or octet, or we may assume that a full outermost shell is reached. Since helium only contains two electrons. They exist, however, only in the first shell, which involves the completion of only two electrons. So the outermost shell of helium is called complete.

How many electrons can fit in each shell?

The first shell (closest to the nucleus) can hold two electrons. The second shell can hold 8 electrons. The third shell can hold 32 electrons. Within the shells, electrons are further grouped into subshells of four different types, identified as s, p, d, and f in order of increasing energy.

Which of the following has expanded octet?

PF5, SF6 and H2SO4 are the examples of expanded octet molecules.