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bonds

forces that hold groups of atoms together and make them function as a unit

ionic bonds

transfer of electrons

covalent bonds

sharing of electrons

polar covalent bonds

unequal sharing of electrons that results in an unbalanced distribution of charge

electronegativity

the ability of an atom in a molecule to attract shared electrons to itself

shielding effect

the nucleus blocks valence shell electron attraction because of the presence of inner-shell electrons

Describe the periodic trends of shielding.

shielding increases down a group

this causes electronegativity values to decrease

greater than 1.7 EN difference value

ionic

between 0.3 and 1.7 EN difference value

polar covalent

0.3 and less EN difference value

non-polar covalent

greater than 50% ionic character \= ?

ionic

between 5% and 50% ionic character \= ?

polar covalent

less than 5% ionic character \= ?

covalent

What are the general rules for determining if a bond is ionic?

greater than 1.7 electronegativity difference

greater than 50% ionic character

ionic

What are the general rules for determining if a bond is polar covalent?

between 0.3 and 1.7 electronegativity difference

between 5% and 50% ionic character

polar covalent

What are the general rules for determining if a bond is covalent?

0.3 and less electronegativity difference

less than 5% ionic character

nonpolar covalent

molecule

a neutral group of atoms that are held together by covalent bonds

diatomic molecule

a molecule containing only two atoms

chemical formula

indicates the relative numbers of atoms of each kind of a chemical compound by using atomic symbols and numerical subscripts

molecular formula

shows the types and numbers of atoms combined in a single molecule of a molecular compound

non-polar covalent bonds

equal sharing of electrons

What are the 2 categories of covalent bonds?

non-polar covalent bonds

polar covalent bonds

unequal sharing of electrons that results in an unbalanced distribution of charge

What's the symbol for the difference in electronegativity?

delta

ΔEN

What's the symbol for the difference in electronegativity?

What happens when an ΔEN value is exactly 1.7?

2 nonmetals \= polar covalent

Only things held together by \_______ \_______ can be considered molecules.

covalent bonds

What are the 7 elements that form diatomic molecules?

bromium (Br)

What are the 7 elements that form diatomic molecules?

bromium (Br)

\
iodine (I)

\
nitrogen (N)

\
chlorine (Cl)

\
hydrogen (H)

\
oxygen (O)

\
fluorine (F)

Where is BrINClHOF located on the periodic table?

7 shape starts at nitrogen (group 15)

bond energy

the energy required to break a bond

What does bond energy give us information about?

the strength of a bonding interaction

Where can bonds occur in electron dot notation?

on the single dots on each side

In nature, bonds want to occur how often?

as often as possible

the octet rule

chemical compounds tend to form so that each atom,
by gaining, losing, or sharing electrons, has an octet
of electrons in its highest occupied energy level

what are double bonds

two pairs of shared electrons

What's the difference between single bonds, double bonds, and triple bonds?

double bonds have higher bond energy and shorter bond length than single bonds

triple bonds have higher bond energy and shorter bond length than single or double bonds (both)

double bonds have higher bond energy and shorter bond length than single bonds

triple bonds have higher bond energy and shorter bond length than single or double bonds (both)

triple bonds

three pairs of shared electrons

How do you find the "more negative" atom in a bond?

whichever has the highest EN value

How many possible arrangements are there when you have 1 central atom with 3 attached?

2

What are the possible arrangements when you have 1 central atom with 3 attached?

pyramidal, trigonal planar

How is the pyramidal molecular shape formed?

the lone pair of electrons cause the "bottom" atoms to push downward, which forms the pyramidal shape

If you only have 2 atoms, the only possible molecular shape is \_______.

linear

What's the bond angle for a linear molecular shape?

180 degrees

What's the bond angle for a bent molecular shape?

105 degrees

What's the difference between trigonal planar and pyramidal molecular shapes?

pyramidal has a lone pair

trigonal planar does NOT have a lone pair

What elements can exceed the octet rule?

anything 3rd energy level and above

pyramidal (what are the properties?)

1 central atom with 3 attached

trigonal planar (what are the properties?)

1 central atom with 3 attached, but no lone pair

tetrahedral (what are the properties?)

4 atoms bonded to 1 central atom

Unshared pairs want the \_______ space away from each other.

maximum

bent molecular shape (what are the properties?)

variation of a tetrahedron

1 central atom and 2 attached

other 2 places are left vacant for the 2 lone pairs of electrons

If your molecule has polar bonds, it may be a \_______ \_______.

polar molecule

What do polar molecules have?

slightly positive sides and slightly negative sides of the entire molecule

What do you need in order to determine if a molecule is entirely polar?

proper geometry to allow it (an axis that can divide positive vs negative)

polar bonds

dipoles

another word for polar molecules

Are polar molecules attracted to each other?

yes

partial symbol

axis

straight line

Not all atoms with polar bonds are \_______ \_______.

polar molecules

symbol to represent a polar bond

the arrow with a line on it

VSEPR theory

repulsion between the sets of valence-level electrons surrounding an atom causes these sets to be oriented as far apart as possible

In metals, the valence electrons are held \_____.

loosely

Do metal atoms lose their valence electrons in metallic bonding?

no, they release them into a sea of electrons

Do metallic bonds create compounds?

no, they're not called compounds

What are the 4 properties that result from a metallic bond?

malleable

ductile

conductivity

luster

luster

the narrow range of energy differences between orbitals allows electrons to be easily excited, and emit light upon returning to a lower energy level (shiny)

ductile

drawn into wires

conductivity

the flow of electrons

malleable

pounded/rolled into sheets

Why are metals malleable?

bonding is the same in all directions, so metals tend not to be brittle

lone pairs of electrons

shift the shape of a molecule

pairs of electrons that are not involved in a bond

Do lone pairs of electrons occupy space?

yes

Why does repulsion occur in electrons?

due to negative-negative repulsion

hybridization

combining of two or more orbitals of nearly equal energy within the same atom into orbitals of equal energy

what shape is sp^3 hybridization

tetrahedral

The interactions between molecules are called \_______ \_______.

intermolecular forces

How do we tend to evaluate intermolecular forces?

boiling point

Intermolecular forces are generally \_______ (stronger/weaker) than bonds that join atoms in molecules.

weaker

Dipoles have \_______ (higher/lower) boiling points than non-polar molecules.

higher

dipole-dipole attractions

attraction between oppositely charged regions of neighboring molecules

What is the strongest intermolecular force?

hydrogen bonding

What is the middle-strongest intermolecular force?

dipole-dipole

How is hydrogen "bonding" represented?

dotted lines

When hydrogen is attracted to FON, it is extra \_______.

strong

What are the 3 highly electronegative atoms that hydrogen is bonded to in hydrogen bonding?

F O N

fluorine

oxygen

nitrogen

All molecules experience \_____ \_____.

London forces

What's the weakest intermolecular force?

London dispersion forces

What's the only intermolecular force among non-polar molecules?

London dispersion forces

formula unit

the simplest collection of atoms from which an ionic compound's formula can be established

Formation of ionic compounds is ALWAYS \_______.

exothermic

Creation of octets in polyatomic ions results in an \________________.

excess or deficit of electrons

Describe the melting point of ionic compounds.

high

Describe the conductivity of ionic compounds.

excellent conductors, molten and aqueaous

Describe the solubility of ionic compounds.

soluble