12 valence electrons

Group 7 elements are also called halogens. Halogens all have 7 valence electrons, meaning they only require 1 more electron to reach the desired 8 in the valence. Since they only require 1 more electron, the halogens are quite reactive.

nine valence electrons

39 Cards in this Set

However, there are three general exceptions to the octet rule: Molecules, such as NO, with an odd number of electrons; Molecules in which one or more atoms possess more than eight electrons, such as SF6; and. Molecules such as BCl3, in which one or more atoms possess less than eight electrons.

This is due to the quantum nature of the atoms, where electrons are arranged into shells: there are 2 electrons in the first called the K shell, 8 in the second (L-shell), 18 in the third (M shell). …

Here the sulfur atom has six electron pairs in 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. An octet would be 3s23p6.

Hydrogen, beryllium, and boron have too few electrons to form an octet. Hydrogen has only one valence electron and only one place to form a bond with another atom. Beryllium has only two valence atoms, and can form only electron pair bonds in two locations.

The two elements that most commonly fail to complete an octet are boron and aluminum; they both readily form compounds in which they have six valence electrons, rather than the usual eight predicted by the octet rule.

Phosphorus can have expanded octet, because it can shift it’s lone pair electrons (3s orbital electrons) to empty 3d obital during excited state and thus can form 5 bonds.

Simple answer: hybridization. Phosphorus only ‘needs’ three more electrons to get a full valence shell of eight, but you’ll notice that it actually has five valence electrons, so in theory all of these could bond. When bonding five times, the s-, p-, and d-orbitals actually fuse to create a hybrid dsp 3 orbital.

Phosphorus can form 5 bonds like in the case of phosphate. While nitrogen is known to make a maximum of 4 bonds (3 covalent, 1 dative covalent).

The outer electrons of phosphorus cannot form strong triple bonds, because the distance between the electrons and the atomic nuclei is greater in phosphorus than in nitrogen. The phosphorus atom often forms compounds in which phosphorus is bonded to five other atoms.

1 Answer. Due to larger atomic size P is unable to form pi bonds and so it is tetra-atomic in which each P atom is linked with 3 other P atoms by 3 sigma bond. But, due to smaller atomic size N forms 1 sigma and 2 pi bonds i.e. triple bonds with other N atom and exists as diatomic molecule.

Phosphorus atoms can bond with oxygen atoms to form ester groups. These can bond with carbon atoms, yielding a large number of organic phosphorus chemicals. These are found in many important biological processes. The phosphoglycerides, for example, are required for fermentation.

Nitrogen atoms will form three covalent bonds (also called triple covalent) between two atoms of nitrogen because each nitrogen atom needs three electrons to fill its outermost shell. The carbon atom has four electrons in its outermost shell and needs four more to fill it.

If you look at the above image you can see that when nitrogen has a positive charge (one less electron), it can form four covalent bonds. Either with single, double, or triple bonds. It is similar to phosphorus in this regard because they both have five valence electrons (four when they have a positive charge).

In the first case, a nitrogen with two bonds and two lone pairs would be −N(−)− . That is, it would have a charge of −1 . −NH− is a secondary amine, and that is more stable than −N(−)− . The anion has two lone pairs, instead of one, and it can donate one of those pairs to grab a proton and stabilize the charge.

Nitrogen tends to form three bonds and have on e lone pair. Oxygen tends to form two bonds and have two lone pairs. Fluorine (and all halogens) tends to form one bond and have 3 lone pairs.

2

As known, nitrogen could form 3 bonds based on octet rule, because it has 5 valence electrons. That means it needs 3 bonds.

Because the nitrogen is only forming 3 bonds, one of the pairs must be a lone pair. Because of this, there is more repulsion between a lone pair and a bonding pair than there is between two bonding pairs. That forces the bonding pairs together slightly – reducing the bond angle from 109.5° to 107°.