Find the geometric structure of: Na₂O PCl₃ H₂S P. S Need an explanation,possibly with electronic configuration (Teacher requires this) ?

3 Answers
Mar 14, 2018

Well, in sodium oxide, #Na_2O#...

Explanation:

...you simply gots an ionic salt composed of #Na^+#, and #O^(2-)# ions...in an extended array .... from memory this is the antfluorite structure...., i.e. the reverse of #CaF_2#...

For #PCl_3#, we simply use VESPER#"..."#around the phosphorus atom there are FOUR electron pairs....#3xxP-Cl# bonds, and one phosphorus-based lone pair... #/_Cl-P-Cl=109.5^@# to a first approx. In practice, the phosphorus lone pair, the which lies close to the phosphorus nucleus, compresses #/_Cl-P-Cl=100^@#.

For #H_2S# we gots another structure BASED on a tetrahedron. And here there are TWO lone pairs localized to sulfur. #/_H-S-H=92.1^@# by measurement. The influence of the two lone pairs in the compression of #/_H-S-H# is apparent.

Elemental phosphorus can occurs as the #P_4# molecule, a tetrahedron. Each atom has 5 valence electrons....three of which are involved in #P-P# bonds, and two are a lone pair on each vertex of the tetrahedron. And as a result of the constrained bond angles, necessarily #/_P-P-P=60.0^@#...#P_4# is an extremely reactive customer, and the element must be stored in water.

Mar 14, 2018

See below

Explanation:

#Na_2O#: Geometric Structure: Bent Approximate angle: 104 degrees Electron geometry: Tetrahedral

Geometric structure and Electron geometry depend on the central atom which here is Oxygen. In this case, oxygen has 2 unbonded pairs of electrons so due to the valence Electron shell pair repulsion, the regular tetrahedral 109.5 angle is reduced to 104 degrees. The Electron geometry is still tetrahedral as there are four pairs of electrons around Oxygen.

#PCl_3#: Geometric structure:Trigonal Pyramid aproximate bond angle: 107 degrees
Electron geometry: Tetrahedral

Geometric structure and Electron geometry depend on the central atom which here is Phosphorus. In this case, Phosphorus has 1 unbonded pair of electrons so due to the valence Electron shell pair repulsion, the regular tetrahedral 109.5 angle is reduced to 107 degrees. The Electron geometry is still tetrahedral as there are four pairs of electrons around Phosporus.

#H_2S#: Geometric Structure: Bent Approximate angle: 104 degrees Electron geometry: Tetrahedral

Mar 14, 2018

see explanation below;

Explanation:

To predict the geometry of compounds you need to know the valence electron of the centre atom and the number of ligands i.e the number of atoms surrounding the central atom..

Then you determine the total number of electrons in the compound by summing up the valence electron of the central atom and the number of ligands..

Then you get the electron number of electron pairs by dividing the total number of electron by #2#..

The electron pair and the lone pair helps to determine the geometric structure of the compound..

The lone pair is determined by subtracting the number of ligands from the electron pair..

If a compound has #2# electron pair, it is said to be Linear,

#3# it is said to be Trigonal planar or pyramidal depending on the number of lone pair,

#4# it is said to be Tetrahedral,

#5-#Trigonal bipyramidal,

#6-#Octahedral..

For #Na_2O#, for example;

Central atom is Oxygen

Valence electron of centre atom(oxygen)#=6#

Number of ligands#=2#

Total number of electron#rArr6+2=8#

Electron pair#rArr8/2=4#

Number of of bonding pairs #=# number of ligands #=2#

Number of lone pair#rArr 4-2=2#

Therefore, the predicted geometry of the compound #Na_2O# is Tetrahedral (#4# electron pairs)

But since it has two lone pairs, it will be termed distorted tetrahedral..

For #PCl_3;#

Valence of phosphorus (central atom)#=5#

Number of ligands#=3#

Total electron#rArr5+3=8#

Electron pair#rArr8/2=4#

Geometry#=#Tetrahedral

Since lone pair #= 1# (i.e #4-3#)

Then if we would further describe it, it would be termed a distorted tetrahedral..

For #H_2S;#

Valence of Sulphur#=6#

Number of ligands#=2#

Total electron#=8#

Electron pair#rArr 8/2=4#

Geometry #=# Tetrahedral