CHEML 1010 Week 10

The valence shell electron pair repulsion (VSEPR) model _____.

describes the three-dimensional arrangement of the atoms in a molecule

Allotropes are _____.

different structural modifications of an element

Carbon dioxide has a _____ geometric structure.

linear

Valence electrons that are not shared between two atoms are called _____.

lone pairs

When a molecule has more than one interior atom, _____.

more than one geometry may be used to describe the molecule

SF6 has a _____ geometric structure.

octahedral

The goal of the VSEPR model is to arrange the position of the atoms and lone pairs surrounding the central atom in a manner that minimizes _____.

repulsion

The localized electron model assumes that a molecule is bonded through the _____.

sharing of valence electron pairs

bond: 4lone pairs: 0geometry:

tetrahedral

Molecular modeling kits are useful in determining the Lewis structure of a molecule.

False

Resonance occurs when there is only one option for the Lewis structure model.

False

The Lewis structure for H2O includes double bonds.

False

The duet rule is based upon the observation that atoms are most stable when surrounded by eight valence electrons.

False

The number of valence electrons of an atom can be found in the row number on the periodic table.

False

Valence electrons include all electrons of an atom.

False

Alkali metals are a group located at the far left of the periodic table; alkali metals have _____ valence electron(s).

1

Magnesium has _____ valence electrons.

2

The octet rule is based upon the observation that atoms are most stable when surrounded by how many valence electrons?

8

Move the terms to complete each statement.

A model that describes the three dimensional arrangement of electrons based on electron repulsion is called the VSEPR model. Two hydrogen atoms form a duet when they have covalent bonds. Diamond and graphite are two allotropes of carbon. Resonance structures show the same connection of atoms but different arrangement of the bonds. An atom that has less than eight electrons surrounding it in a compound is said to be electron deficient . The number of outermost electrons is the number of valence electrons .

Match the number of valence electrons with the correct compound. CH4 PBr3 OF2 CH2O O3 SiCl4

CH4= 8 PBr3= 26 OF2= 20 CH2O= 12 O3= 18 SiCl4= 32

The _____ of a molecule visually describes the two-dimensional arrangement of atoms and valence electrons in a molecule.

Lewis structure

What atoms always obey the octet rule?

Oxygen, fluorine, nitrogen, carbon

Some compounds have more than one Lewis structure.

True

The first step in creating a Lewis structure is to determine the total number of valence electrons for the entire molecule.

True

A model that describes the three dimensional arrangement of electrons based on electron repulsion is called the --_____ model.

VSEPR

Different structural modifications of an element are called _____.

allotropes

An example of an atom with 3 valence electrons is _____.

aluminum

bond: 2lone pairs: 2geometry:

bent

In a molecular modeling kit, a black ball with 4 holes most likely represents the element _____.

carbon

bond: 3lone pairs: 0geometry:

trigonal planar

bond: 3lone pairs: 1geometry:

trigonal pyramidal