chemistry is
the study of matter and the changes that it undergoes
Kinetic Molecular Theory
-Particles of matter are always in motion-The kinetic energy or speed of these particles increases as temperature increases.
solids
-very low KE( particles vibrate but cant move around)-fixed shape and volume
liguids
-low ke (particles can move around but still close together-variable shape-fixed volume
Gases
-high ke(particles can separate and move throughout container-variable shape and volume
matter
Anything that has mass and takes up space
atom
the smallest unit of an element that maintains the properties of that element
element
A pure substance made of only one kind of atom
compound
substance made of 2 or more types of atoms that are chemically bonded
molecule
type of compound in which bonds are covalent bonds
physical property
characteristics that can be observed or measured without changing the identity of a substance
chemical property
relates to a substances ability to undergo changes that transform it into a different substance -easiest to see when a chemical is reacting
Physcial Properties
temp. , amount, color, odor,melting point,solubility,electrical conductivity, and hardness
chemical Properties
rust,combustion,tarnish,and hardening
extensive
depends on the amount of matter
intensive
do not depend on the amount of matter present
physcial change
-changes the form of a substance without changing its identity -properties remain the same
chemical change
-changes the identity of a substance-products have different properties
signs of a chemical change
-change in color or odor-formation of gas-formation of a solid(two liquids make solid)-change in light or heat
matter flowchart
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pure substance:element
composed of identical atoms
compound
-composed of two or more elements in a fixed ratio-properties differ from those of individual elements
Law of Definite Composition
A given compound always contains the same, fixed ratio of elements
Law of Multiple Proportions
elements can combine in different ratios to form different compounds
mixtures:solution
-homogeneous-very small particles-no tyndall effect
mixtures:suspension
-heterogeneous-large particles-tyndall effect-particles settle
mixtures:colloid
-heterogenous-medium-sized particles-tyndall effect-particles dont settle
representative elements
elements from groups 1, 2, and 13-18 in the periodic table, they represent each category of metals,nonmetals,and metalloids;as well as representing each state of matter, and the A represents the number of valence electrons found in the elements of that group
transition metals
groups 3-12,these metals are solid at room temp(except for mercury), and B represents the number of valence electrons
inner transition metals
underneath the periodic table,lanthanide beleongs in period 6 and actinide in period 7, these are also solid at room temperature
periods and series
rows on the periodic table
groups and families
Vertical columns on the periodic table
metals
located on the left side of staircase, they are malleable,ductile,good conductors of heat and electricity,solid at room temp.(except for mercury),and are shiny
nonmetals
on the right side of the staircase on the periodic table(except for hydrogen),brittle,not ductile,poor conductors of heat and electricity,and have low shine. Most are gases at room temp. but some are solids and Bromine is a liquid.
Metalloids
Elements that have properties of both metals and nonmetals.may behave as a metal under some conditions but may behave as a nonmetal under other conditions
alkali metals
Group 1(excluding hydrogen),very unstable,highly reactive,likely to bond with other elements and lose its valence electron,extremely soft metals. Very abundant in nature,low density,low melting and boiling points.
alkaline earth metals
Group 2, very reactive,likely to bond with other elements and lose 2 electrons. Bond similarlyand have similar properties.
Halogens
Group 17,want to gain one more valence electron to make outer energy level full,will easily bond with alkali and will form salt
noble gases
Group 18,non reactive and most stable. Outer shell is full so does not wish to bond with others.High density,high melting point,colorless,odorless,and tasteless.
lanthanide series
rare earth elements" part of period 6,all have common properties to the element Lanthanum
actinide series
radioactive metals part of period 7,all have common properties of the element Actinium.