Does a molecule of polycentric atom have lone electron pairs? If so, what should I do? Senior 2 Chem

For example, ethylenediamine nh2ch2ch2nh2

Ethylenediaminetetraacetic acid.

Root ion (-oocch2)2n-ch2-ch2-n(ch2coo-)2

A molecule of eventful multicentric atoms that contains lone electron pairs.

Since it does not belong to the simple configuration.

As for the valence electron pair, it is calculated separately according to the individual central atoms, and then its configuration is two or more simple.

For example, dsp3 and sp3 are nested to form a new configuration.

Therefore, it will not be calculated according to the requirements of the visper model.

If you are interested in learning more about its detailed structure, you can refer to the Red Skin's High School Chemistry Competition.

There are details above.

This is beyond the requirements of the college entrance examination.

For example, the molecule ABX, a is the central atom, x is the number of b atoms, and the number of lone electron pairs = (the number of outermost electrons of a atom - x the absolute value of the valence state of b atom) 2

For example, CH4 lone electron pair=(4-4 1) 2=0NH3 lone electron pair=(5-3 1) 2=1SO2 lone electron pair=(6-2 2) 2=1H2S lone electron pair=(6-2 1) 2=2cCl4 lone electron pair=(4-4 1) 2=0

Of course! It doesn't matter how many centers there are, such as ethanol, o has arc electron pairs, one is combined with h, one is combined with c, and the remaining three pairs are.

Lone electron pairs: Paired valence electrons that are not combined or shared with other atoms.

It is first necessary to know the number of outermost electrons of that atom and then according to itValencyJudging into the number of bonds, generally the outermost layer of 2 electrons is stable or 8 electrons are stable, exceptElectron pairs are sharedThere are no shared electron pairs other than thatLone pairs of electrons

How lone pairs of electrons are calculated and applied:Formula: (a-xb), a is the number of valence electrons of the central primordial Qisheng non, which is the number of outermost electrons. x is sigma.

The bond is the number of paired atoms, and b is the number of electrons that the paired atom can hold.

Formula; One in two (a-xb).

A is the number of valence electrons of the central atom, which is the number of electrons in the outermost shell, X is the number of sigma bonds, which is the number of paired atoms, and B is the number of electrons that can also hold Xiaohui. For example, the H20 central atom is oxygen. A is the outermost electron number of oxygen 6, x is the number of paired atoms 2, b is the number of electrons that can be accommodated by the paired atom is 1, half (6-2 1) = 2 lone pair electrons is 2.

Valence shell electrons of the central atom.

Logarithm (note that it is not the number of valence electrons) vertical height = logarithm of lone electrons of the central atom + bond formation between the central atom and the surrounding atoms.

Electron logarithms. 1) Find the high sensitivity to the central atom first, generallyValencyThe numerical value is larger, and the bound atoms are moreElectronegativitySmaller (except H).

(2) Look at which main group the central atom is in, and the group number is the outermost electron number.

(3) Then look at the number of electrons required for the atom to bind to the central atom (8-its group number).

(4) The number of outermost electrons of the central atom minus the total number of electrons required by the surrounding atoms, divided by 2 is the number of lone electron pairs of the central atom.

(5) Count how many atoms are combined with the central atom around the number, and the atom of the center is bonded with the surrounding atoms, and the number of electron pairs is a few.

The calculation of lone pairs of the central atom according to the Communal trap formula 1 2 (a-xb) is more suitable for the case where the central atom is one.

There can only be one bond between every two atoms, so that in C2H2 each C atom forms a bond with an H atom, each C atom has 5 valence shell electrons, and only 3 more electrons are needed to reach an 8-electron stable structure.

So every c atom has: 1 2 (4-1-3) = 0 lone pairs of electrons.

In the same way, in C2H4, each C atom forms 2 bonds with 2 H atoms, there are 6 valence shell electrons, and 2 electrons are needed to reach the 8-electron stable structure. In the first place, each c atom also has: 1 2 (4-2-2) = 0 lone pairs.

In fact, in general, the c atom in the organic molecule does not have lone pairs, and all of them are used to form bonds or bonds. To determine the hybrid form of the C atom, one only needs to look at how many atoms it binds to. If Jianpeinian combines 4 atoms, it is sp3 hybridization; If 3 atoms are combined, it is sp2 hybridization; If two atoms are combined, it is sp hybridization.

Generally, it is to look at which group the atom that the central atom is bound to, and you will know how many electrons there are in its outermost shell, and then 8-the outermost electro-guess number = the number of electrons required. (for master family elements).

For example, when speculating the molecular structure of CO2, the central atom selects the C atom (because of its large valency value, there are many atoms combined), and the outermost shell of the central C atom has 4 electrons (the C element is in group IVA).Then look at the O atom bound by the C atom in the VIA group, and know that the O atom has 6 electrons in the outermost shell, and 8-6=2 electrons are needed to achieve the stable structure of 8 electrons, and the two O atoms need a total of 2 2=4 electrons.

Then the number of lone electron logarithms of the central c atom = (4-2 2) 2 = 0In addition, to combine two O atoms, two bonds need to be formed, the number of bond electron pairs is 2, and the valence macrosphere electron pairs of the central C atom are 0+2=2It is speculated that the C atom is hybridized with Sp2 to form a linear molecule.

The formula for the number of lone electron pairs on the central atom is the total number of valence electrons - the number of bonding electrons (or ligand number 2) 2, the central Lee Jixiao atom has an empty valence electron orbital and can accept the lone pairs provided by the ligand to form a coordination bond or accept the ligand's bond electrons to bond the metal atom or ion. Lone pairs refer to the fact that in addition to the bonded electrons used to form covalent bonds, there are often nonbonding electrons in the outermost electron shell of the atom that are not used to form covalent bonds. These unbonded pairs of valence electrons are called lone pairs.

The solitary blue of the atom is used to determine the number of electrons, and the electronic configuration diagram can be drawn according to the principle of lowest energy.

Determination of the number of lone pairs of electrons on the central atom of the molecule, the number of lone pairs of electrons on the central atom = (a xb) 2

where a is the number of valence electrons of the central atom, and for the main group element, the number of valence electrons is equal to the number of outermost electrons of the atom; x is the number of atoms bound to the central atom; b is the maximum number of electrons that can be accepted by the atom bound to the central atom, hydrogen is 1, and the other atoms are "8 minus the number of valence electrons of the atom".

For example, the ammonia molecule has a lone pair of electrons on the nitrogen atom; There are two pairs of lone pairs of electrons etc on the oxygen atom of the water molecule. Because the electron cloud of lone pairs is larger than that of bonding electrons, it has a stronger repulsive effect on bonding electrons, resulting in a decrease in the bond angle of the molecule.

For example, methane has no lone pair of electrons, and the bond angle of ammonia and water molecules is 107° and respectively. When describing the geometry of the molecule, lone pairs are not included, so the methane molecule is tetrahedral; The ammonia molecule is triangular pyramidal, while the water molecule is curved.

The central atom of the ion sock group may or may not have lone electron pairs. An ionic cluster is a molecule composed of several atoms, in which at least one atom loses or gains electrons, making the whole molecule an electrically charged ion. The ionic basis group central atom refers to the central atom of this ionic cluster, i.e., the atom that has lost or gained electrons.

If the central atom of the ion cluster loses electrons, then it will have a lone electron pair. For example, the chloride ion (Cl-) is an ionic cluster whose central atom is the chlorine atom, and the chlorine atom loses one electron, so the chloride ion central atom has a lone electron pair.