Atom
Basic particle for everything. Consists of a positively charged center, aka the nucleus surrounded by negative charges.
elements
substance that cannot be broken down into any toher substance by chemical or physical means.
physical change
alter form/appearance but substance is still the same ex: phase change, shape change)
chemical change
the substance changes to a new one by breaking down into two or more other substances, or combining Atoms rearrange to form new substances ex: oxidation. combustion
Law of conservation of mass
matter is not created or destroyed
solution
mixture of a liquid and dissolved solid
solute
solid
solvent
liquid
reactants
substances that undergo chemical change
products
New substances that form
What does every chemical and physical change include?
a change in energy
What are two types of changes in energy?
exothermic and endothermic
endothermic change
change where energy is absorbed because there is more energy needed to break the bonds of the reactants. Often the area around becomes cooler due to this. Ex: baking soda (Reactant) and vinegar
exothermic change
change where energy is released as there is excess energy after breaking the bonds of the reactants. The energy is often released as heat.
chemical energy
energy the is stored in chemical bonds between atoms.
Periodic table is organized by
groups and periods
valence electrons
electrons with the highest energy. Atoms are more stable with 8 valence electrons. In the outermost orbital
Chemical Bond
force of attraction that hold atoms together as result of rearrangement of electrons between them.
Groups
vertical columns same # of valence
Periods
horizontal rows same # of orbitals
atomic number
the # of protons (usually equal to the # of electrons )
atomic mass
Neutrons and Protons are where?
are in the Nucleus
Electrons are where?
are in orbitals
Isotopes
atoms of the same element with different # of neutrons. Protons don't change. Change in neutrons can be found in atomic mass.
Ions
Have unequal # of electrons and protons. Protons don't change so number of electrons can be find from the charge.
cations
positively charged
anions
negatively charged.
Orbital limits
2, 8, 18, 32
Bohr Model Diagram
Shows it all with a circle nucleus with the protons and neutrons. The orbitals are then drawn with electrons.
Lewis Dot Structure
only the VE
Molecules
a neutral group of two or more atoms bound together by chemical bonds.
Compound
Substance made of 2 or more atoms combined in a set ratio.
Chemical Formula
Ratio to make a compound, represents compound. Ex: Carbon Dioxide which is CO2 H20 water KCl Potassium Chloride or salt
Mixture
made of two substances that are together but not chemically bonded. Is either Homogenous or Heterogenous
Heterogenous mixture
Easily separated, often can see different parts (salad, Italian dressing)
Homogenous mixture
evenly mixed, cannot see different parts, difficult to (ex sugar and water)
Types of Bonds
Metallic, Ionic, Covalent
Metallic bonds
metal atoms lose electrons easily, so bonds form between positive metal ions & the electrons surrounding Ex: aluminum foil
Ionic bonds
Attraction between opposite charged ions causes and ionic compound. usually form between metal and non-metal
Covalent Bonds
bonds usually form between nonmetal bonds. when atoms share electrons.
Polar
unequal sharing of electrons
Nonpolar
equal sharing of electrons
pH scale
range of 0-14 indicates concentration of H+ ions
Bases
have hydroxide ion OH-. Bases are the highest numbers in the pH scale
acid
have hydrogen ions H+, hydrogen atoms that lost its electron. Acids are the lowest on the scale.