4.2, 4.5, 9.11

Why do bonds occur?

forming bonds lowers the energy of the system

ionic bonds are between…

usually metals and nonmetals —> a cation and an anion

covalent bonds are between…

usually nonmetals

diatomic elements

pure substances made of molecules containing exactly 2 atoms of the same element

list of diatomic elements

H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂

polyatomic elements

polyatomic elements are pure substances made of molecules containing 3 or more atoms of the same element

list of polyatomic elements

P₄, S₈

monatomic species

Chemical elements that exist as stable, unbonded single atoms under standard conditions. Because their valence electron shells are completely full, they have no chemical reason to bond with other atoms

beware of ____ when elemental names are being used!!!

CONTEXT
(ex: when we say “hydrogen reacts with oxygen to form water” we’re talking about hydrogen MOLECULES and not individual ATOMS bc hydrogen atoms can be found in the starts")

empirical formula

the simplest, most reduced whole-number ratio of atoms of each element in a chemical compound

CH₂O

molecular formula

the exact number and type of atoms of each element present in a single molecule of a compound

C₆H₁₂O₆

4 ways to represent molecules

Molecular formula (CH₄), Structural Formula, Ball-and-stick modle, space-filling model

chemical formulas of ionic compounds are always given as ______ formulas

empirical

Lattice Energy

the huge amount of energy released when separate gas ions crash together to form a solid ionic crystal/solid

X²⁺(g) + 2 Y^-(g) →

XY₂(s)

Magnitude of Lattice Energy- what determining factor come first?

Ion Charge dictates trend FIRST
Ionic Radius (r) dictates trend SECOND

what has the smallest atomic radius on the periodic table?

Helium

what is the smallest ION?

Hydrogen+

|LE| is _______ to MAGNITUDE of charges

PROPORTIONAL (-123 kj/mol > -100 kj/mol..treat it as positive numbers)

|LE| is ______ ______ to DISTANCE

INVERSELY PROPORTIONAL (Greater distance = Smaller LE)

Smaller DIstance = Greater LE = Releases ____ energy

MORE