Chem Chapter 1-3

Atomic Number

number of protons in nucleus

Mass Number

Number of protons and neutrons in nucleus

Valence Electrons

Electrons in outermost shell

Coulombs Law

likes repel, opposites attract, larger electrical charges = stronger push/pullcteO

Octet Rule

Every atom wants full shell = 8 valence electrons except H

Ion

charged atom

Cation

Positively charged atom

Anion

negatively charged ion

Electronegativity

how much an atom “likes” or holds on to shared electrons in a covalent bond

Ionization Energy

energy required to remove electron farthest from nucleus

Atomic radius

distance from nucleus to edge of electron cloud

Pure substance

an element or a compound

mixture

combination of two or more pure substances

Density

amount of mass in a certain volume

Density formula & units

d=m/v, g/cm³ and g/mL

homogenous mixture

cannot see separate parts (kool-aid)

heterogenous mixture

can see separate parts (trail mix etc)

Physical properties

color, mass, density, volume

Chemical properties

flammability, reactivity with water, toxicity

Difference between chemical and physical properties

physical can be observed without changing identity or chemical identity of substance, chemical alters to form new material

quantitative

numbers (mass)

qualitative

color change, flame test, precipitate forming

Atomic Mass Equation

(%/100 x ) + (%/100 x __)

4 types of orbitals

s,p,d, and f

shape of s orbital

sphere

shape of p orbital

dumbbell

shape of d orbital

clover

shape of f orbital

flower

Hunds Rule

fill orbitals one at a time before doubling up

Pauli Exclusion Principle

orbital can only hold 2 electrons with opposite spins

Atomic Radius trend

increase down a group, decrease left to right

Electronegativity trend

decrease down a group, increases left to right

Ionization Energy trend

decrease down a group, increases left to right

Group 1 metals

Alkali Metals

Group 2 metals

alkaline earth metals

Group 17 elements

halogens

Group 18 elements

noble gases

Bond angle of tetrahedral

less tan 109.5

bond angle of trigonal planar

120

bong angle of linear

180

Diatomic Elements

H,N,O,F,Cl,Br,I