Question

1. chemical name: selenium pentafluoride cation formula: sef5+

lewis electron - dot structure:

perspective drawing with bond angles:

standard electron geometry:
molecular geometry:
hybridization of central atom:
is the molecule polar, nonpolar, or ion?

Explanation:

Step1: Determine valence - electrons

Selenium (Se) has 6 valence electrons and each fluorine (F) has 7 valence electrons. The ion has a + 1 charge. So the total number of valence electrons is \(6 + 5\times7-1=40\).

Step2: Draw Lewis structure

Place Se in the center and F around it. Connect Se and F with single - bonds first, using 10 electrons. Then distribute the remaining 30 electrons as lone - pairs on F atoms to satisfy the octet rule. Se can have an expanded octet.

Step3: Determine electron geometry

The central Se atom has 5 bonding pairs and 1 lone - pair. Using VSEPR theory, the electron geometry is octahedral (6 electron - domains).

Step4: Determine molecular geometry

With 5 bonding pairs and 1 lone - pair, the molecular geometry is square - pyramidal.

Step5: Determine hybridization

For 6 electron - domains around the central atom, the hybridization of Se is \(sp^{3}d^{2}\).

Step6: Determine polarity

The molecule is polar because the lone - pair on Se causes an uneven distribution of electron density and the bond dipoles do not cancel out.

Answer:

Lewis electron - dot structure: Se is in the center with 5 single bonds to F atoms, and each F has 3 lone - pairs.
Standard electron geometry: Octahedral
Molecular geometry: Square - pyramidal
Hybridization of central atom: \(sp^{3}d^{2}\)
Is the molecule polar, non - polar, or ion? Ion (it is a cation) and polar.
Perspective drawing with bond angles: In a square - pyramidal structure, the bond angles between axial and equatorial F - Se bonds are approximately \(90^{\circ}\), and the bond angles between equatorial F - Se bonds are less than \(120^{\circ}\) due to the lone - pair repulsion.