bonding (tania please study this)

wait i didnt know i could type a desc omg hello favs!! how have yall been?? tbh a lil worried for this one...

are atoms more stable with a full shell or a half full shell

full shell- the atom/ion has all the valence electrons it needs

what is formed when an atom gains or loses electrons

an ion

valence electrons (typically) are equal/related to the

group number

what is a lewis dot diagram

the element symbol surrounded by dots that represent valence electrons

the charge on the ion is known as the

oxidation number

how are ions written

element symbol w superscript showing the charge

ionic bond is formed when

electrons are transferred from one atom to another

metals __ electrons and nonmetals __ electrons

lose, gain

atoms are attracted to each other due to

opposite charges (one element has a net pos charge (the metal/cation) and the other has a net neg charge (the nonmetal/anion) - think of placement on the periodic table))

ionic substances are sometimes called

salts

salts are generally

neutrally charged (ex: NaCl)

to name an ionic compound, first name the ____ then the ____ and change the ending to _____

cation, anion, -ide

to write a chem formula:

first find the charges and determine how many of each ion you need to form a neutral compound

if the cation is a _____ ___, then you specify the charge with a ____ _____

transition metal, roman numeral

three transition metals where roman numerals are not needed

argon (1+), zinc (2+), and cadmium (2+) (these always have the same charges)

two group A metals that need roman numerals

sn (2+ or 4+), Pb (2+ or 4+) (these atoms have variable charges)

what is a polyatomic ion

groups of atoms that behave as one unit

when do polyatomic ions need parentheses

when more than one is used in a formula, otherwise they are treated like a single ion

what are the three types of bonds

ionic, covalent and metallic

how is an ionic bond formed?

electrons are transferred from a metal atom (left side of the staircase) to a nonmetal atom (right side of the staircase)

what happens to the metal and nonmetal when they transfer electrons? (ionic bond)

they form their respective ions

why are metals and nonmetals attracted to each other? (ionic bond)

cations and anions are attracted to each other

how do you name ionic bonds/ions

name the metal, then the nonmetal and change the ending of the nonmetal to -ide

what is the structure of an ionic bond

lattice (crystal) structure is present in many ionic compounds

what are properties of the ionic bond lattice structure?

good electrical conductor, high melting point, strong pos-neg attraction, water soluble

ex of a VERY COMMON ionic bonded molecule

NaCl (salt)

when/how is a covalent bond formed?

electrons between elements r shared (shared to fill each element's octet)

elements with covalent bonds are almost always

nonmetals!! (right of the staircase + hydrogen)

what are covalent compounds called

molecules

how do u name a covalent compound?

prefixes (will go in depth later) + the -ide ending

nonmetals bonded to each other have (similar/different) properties to regular nonmetals

similar - properties include low melting point, poor conductors, low solubility in water

ex of covalent compounds

water (h20), ammonia (NH3), chlorine (Cl2)

how is a metallic bond formed

when a metal is bonded to another metal (woah man who saw that coming!)

why are metallic bonds related to the term "sea of electrons"

electrons move within the metallic atoms

what does the movement of electrons in metallic bonds allow for

ease of electron transfer between atoms, atoms can slide past each other, lustrous, very high melting point

alloys

different metallic atoms bonded to one another exhibit unique properties due to difference in atomic size

what is it called when molecular compounds share their valence electrons?

a covalent bond!

what do covalent bonds form between?

two nonmetals

how do you name a covalent compound?

name the first element, then name the second one and change the ending to -ide (but use prefixes to show amount of atoms of each element)

mono

1 - omitted if on the first element

di

2

tri

3

tetra

4

penta

5

hexa

6

octa

8

hepta

7

nona

9

deca

i love deca tbh like its a 10/10 for me! (it means ten i hope yall thought thsi was funnt im really stressed tehse days) #gettheedge

what should you NEVER DO when writing covalent compound formulas

reduce subscripts (to clarify, never reduce subscripts)

can you use prefixes for ionic compounds

no!

what is a lewis dot diagram

a diagram that shows electrons available for bonding (the outermost valence electrons)

review the rules for how to draw a dot diagram

exception to the octet rule: hydrogen can only have __ valence electrons

2

exception to the octet rule: beryllium can only have __ electrons

4

exception to the octet rule: boron is stable with __ electrons

6

what periods have an expanded octet

any central atom that is from 3-7 have expanded octets

what is an expanded octet?

the ability (of a central atom) to accommodate more than 8 electrons

bonds, polarity: how large must the difference in electronegativity be for there to be an ionic bond formed?

greater than 1.7

what type of bond is formed when the difference in electronegativity is small?

a covalent bond

when is a covalent bond nonpolar?

electrons are shared equally and the overall charge is neutral (electronegativity difference is

when is a covalent bond polar?

when electrons are not shared equally (electronegativity difference between .4-1.7)

the more electronegative atom attracts more electrons

creating a partially negative region of the atom

the less electronegative region of the atom becomes

slightly positive

what are the two ways to show polarity of a molecule?

letter delta to show partial charges OR arrow that points in the more electronegative direction/atom

molecular polarity: what makes a molecule nonpolar?

if all the bonds are nonpolar

if a molecule has a ___ bond, then the whole molecule is polar

polar (this applies most of the time, but not always)

a molecule is nonpolar if

the central atom has no lone pairs + has all the same types of atoms attached to it (basically symmetry)

a molecule is polar if

the central atom has lone pairs OR the central atom has no lone pairs but different atoms attached to it

covalent bonds can be

single, double or triple

single bond (covalent)

two atoms share one pair of electrons (1 sigma bond)

double bond (covalent)

two atoms share two pair of electrons (1 sigma and 1 pi bond)

triple bond (covalent)

two atoms share three pair of electrons (1 sigma and 2 pi bonds)

hybridization

the concept of mixing atomic orbitals to form new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) suitable for the pairing of electrons to form chemical bonds in valence bond theory

hybrid orbitals are formed by

mixing atomic orbitals of comparable energies

steps to determining hybridization

resonance

concept in which two or more Lewis structures for the same arrangement of atoms (resonance structures) are used to describe the bonding in a molecule or ion

how is resonance shown

double headed arrow is placed between the molecules resonance structures

what is a resonance structure?

various forms of the same molecule where the electrons have transferred from one region to another

what is a resonance hybrid

each individual resonance structure is averaged into a resonance hybrid which is both the true shape of the molecule and the most stable resonance form.

formal charge equation

Formal charge = valence electrons - nonbonding electrons - ½ the bonding electrons

what is formal charge

Sometimes there are more than one possible structure so to find the most likely structure you will need to calculate the formal charge