Bonding, Lewis Structures, Geometry and Intermolecular Forces
A molecule that has two bonds and lone pairs has what shape?
Bent
A molecule with two bonds and two lone pairs on the central atom has what shape?
Bent
Intramolecular forces are also known as what?
Bonds
Elements that can form double/triple bonds are what?
CONPS
Water's crystal structure causes it to be less what when it freezes?
Dense. so it floats.
What are two things to do to an ion Lewis?
Draw brackets and charge
Ability to attract shared electrons is called what?
Electronegativity
What is an atom's ability to attract shared electrons called?
Electronegativity
When intermolecular forces of liquid molecules are overcome, they what?
Evaporate
Ethanol and Ether have the same formula, but different structures. They are called what?
Isomers?
Which of the following is/are ionic?: KCL, Na2O, CBr4, HF
KCL, Na2O
The 3-dimensional structure of an ionic compound is called a what?
Lattice
A molecule that has two bonds and no lone pairs is what shape?
Linear
A molecule with two double bonds on the central atom has what shape?
Linear
A molecule is normally polar if it has _____ on the central atom?
Lone pairs
To achieve an octet, potassium will _______ one valence electron.
Lose
Which kind of atoms usually have less than 4 valence electrons?
Metal
Ionic compounds do not partner up to form what?
Molecules
In the molecule NOF, ______ is in the middle because?
N because it has the fewest number of valence electrons
In an ionic Lewis structure, how many electrons around the cation(s)? The anion(s)?
No electrons around the cations. 8 electrons around the anions.
Octet configuration is the same as what kind of gas?
Noble gas
Is CH4 polar or nonpolar?
Nonpolar
Is CO2 polar or nonpolar?
Nonpolar
Is NH3 polar or nonpolar?
Nonpolar
A bond in which electrons are shared equally is called what?
Nonpolar covalent
Elements in the same main group have the same what?
Number of valence electrons
To form the molecule SF6, sulfer must exhibit what?
Octect exception -- expanded to 12
In the molecule OF2, _______ is in the middle because?
Oxygen because it is unique (only one)
What happens when metals are found uncombined?
Their valence electrons are delocalized or passed around atoms in what is known as an electron sea
How many times to atoms of hydrogen bond?
These atoms bond only once and never get lone pairs.
How do ionic compounds partner?
They pack together into a 3-dimensional structure called a lattice in order to maximize electrostatic attractions between ions.
What is a triple bond?
Three pairs of electrons shared between the same two atoms
Why is it difficult to determine the number of valence electrons in transition elements?
Transition elements have 'd' orbitals that are only partially filled
A molecule with three bonds and NO lone pairs on the central atom has what shape?
Trigonal Planar
A molecule with three bonds and one lone pair on the central atom has what shape?
Trigonal Pyramid
If a molecule has three bonding pairs and one lone pair on the central atom, what is its shape?
Trigonal pyramidal
How many electrons does a line represent in a Lewis structure?
2
Does a noble gas combine with other elements?
A noble gas does not combine with other elements
What is a lone pair of electrons?
A nonbonding pair or unshared pair of electrons
When an ion has a charge of -3 what must you do?
Add 3 valence electrons
Covalent bonds form between what?
Two nonmetals
Covalent bonds are usually formed between what?
Two or more nonmetal atoms
What is a double bond?
Two pairs of electrons shared between the same two atoms
Polarity is defined in chemistry as what?
Uneven distribution of electrons
The only electrons involved in bonding are what?
Valence
When do metal atoms become ions?
When their electrons are lost and they then become positively charged
The open crystal structure of H2O means that ice what?
Is less dense than water/floats
For structures of ions you must do 3 extra things. What are they?
1. Add electrons for negative charge/subtract for postive 2. Enclose in square brackets 3. Write charge outside
List some of the physical properties affected by intermolecular attractions
1. Melting and boiling points 2. Surface Tension 3. Evaporation and Vapor Pressure
How many valence electrons are in the molecule HC2H3O2?
24
What do a line or two dots between element symbols represent?
A bond
A non-bonding electron pair is also called what?
A lone pair.
Atom that is always in the center of a molecule?
Carbon
What is the central atom and the number of valence electrons in the Lewis structure for CHOF?
Central atom is C and the number of valence atoms is 18
What is the central atom and the number of valence electrons in the Lewis structure for SiCL4?
Central atom is Si and the number of valence electrons is 32
In what kind of bonds are electrons shared?
Covalent bonds
The most electronegative element is called what?
Fluorine
Hydrogen bonding forces account for surface tension, heat required to evaporate, and high OR low boiling points?
High
Atom that is never in the center of a molecule?
Hydrogen
The strong intermolecular force present in water is called what?
Hydrogen bonding
Water's strong intermolecular forces are called what?
Hydrogen bonds
Exception to Octet rule
Hydrogen, most stable as a DUET because its only shell does not have a p sublevel
A bond in which electrons are not shared at all but are take is called what?
Ionic
Type of bond with no sharing electrons
Ionic
In what kind of bonds are electrons transferred from one atom to another?
Ionic bonds
If a molecule has three bonding pairs only, what is its shape?
Plane
Is H2O polar or nonpolar?
Polar
Is O2 polar or nonpolar?
Polar
The larger the electronegativity difference between two bonding atoms, the more ____ the bond
Polar
A bond in which electrons are shared unequally is called what?
Polar covalent
Bond with unequal sharing of electrons is what?
Polar covalent.
Electron pairs on the same molecule ______ each other
Repel
What is the shape of a molecule based on?
Repulsion between electron pairs
What five elements can form multiple bonds?
S,P,O,N,C
Intramolecular forces are stronger or weaker than intermolecular forces?
Stronger
Polar molecules usually have stronger or weaker intermolecular forces than nonpolar molecules?
Stronger
What are isomers?
Substances that have the same general formula but different atomic arrangements (ex. C2H6O can be either H3C-CH2-O-H or H3C-O-CH3)
A central atom with four bonds would have what shape?
Tetrahedron
What is the structure that involves four bond angles of 109.5 called?
Tetrahedron
What helps us understand why metals are good conductors?
The model of the electron sea
Octet rule
The octet rule is a chemical rule of thumb that reflects observation that atoms of main-group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.
Ionic compounds exist in what kind of a ratio?
The simplest ratio known as a formula unit
When a molecule is polar, it has partial positive and negative charges shown as what?
d+ and d-
valence electrons
electrons in an atoms out s and p orbitals
number of valence electrons of an atome
equal to its group number
only electrons involved in bonding
valence electrons