Powerpoint Exam 1 Flashcards
chemistry
study of the composition properties and interactions of matters
elements
building blocks (alphabets) of matters - pure substances that cannot be separated into simpler substances by ordinary laboratory process
example of elements
oxygen, hydrogen, carbon, gold
building blocks of matter
1 oxygen + 2 hydrogen –> water
1 carbon + 2 oxygen –> carbon dioxide
as of 2007 how many known elements are there and how many can be found in nature?
117 known elements
- 94 can be found in nature
the elemental substance
- each element has it sown unique physical and chemical properties
- each has its own name
- some are named for their appearance, others for planets, mythological figures, scientists, or places
symbols of elements
consists of 1 or 2 leters
- Capital and lower case
particular nature of matters
- macroscopic
- submicroscopic
- macroscopic
- properties and interactions of submicroscopic particles of atoms and molecules determines the properties and behaviors of matter we experience and observe macrocopicly
three terms for the submicroscopic particles
atoms
molecules
ions
atom
smallest particle of an element that can exist and still have chemical properties of the element
molecules
2 or more atoms joined together in a specific arrangement
ions
atoms or a group of bonded atoms with an electrical charge
all atoms of a given elements are?
identical
- the atoms of a given element are different from those of any other element
what is the basic unit for chemical changes/chemical reactions?
atom
molecular view of an element
one type of atoms in each elements
molecules
- group of two or more atoms joined in a specific geometrical arrangement and behave like a single unit
classify molecules by the number of atoms
- Diatomic molecule
- triatmic
- tetratomic
classify molecule by the type of attoms
homoatomic molecules
heteroatomic molecules
homoatomic
- molecules in which all atoms present are of the same kind
- pure substance containing homoatomic molecules must be an element
heteroatomic molecules
- molecules in which two or more kinds of atoms are present
- a pure substance containing heteroatomic molecules must be compounds
what is matter? and example
matter is anything which has mass and takes up space (volume)
ex: sand (solid)
- water (liquid)
- air (mixture of gases)
- human body (solid, liquid, gas)
what kind science is chemistry?
empirical science
- based on the results of experiments/observations
common types of measurements in chemistry
Length - m
Mass - g
Volume - L
Time - duration of experiment or observation
certain digits
given by the smallest grid
uncertain digit
by estimate
precision of a measurement depends on the?
instruments
the uncertain digits is always the?
right most digit
significant figures
the digits in any measurement that are known with certainty plus 1 digit that is uncertain (estimate digit)
sig fig - multiplication and division
answer should contain the same number of sig fig as the measurement with the least number of significant digits
sig fig - +/-
answer many not have any more decimal places than the least accurate number
exact numbers
counting
definition
unit conversion
measure number
obtained by using instruments
Density
- the ratio between mass and volume
D = M/V
periodic table
- graphical display of elements
- elements are arranged by increasing atomic number
- elements with similar properties are placed in same column of the display
periodic table: rows and column
- 7 rows: 7 periods
- 18 columns: 18 groups (8 group a and 10 group B)
major groups in the period table
- alkali metals (1st column - except for helium)
- alkali earth metals (2nd column)
- transition metals (3-12th column)
- halogens (2nd to last column or 17th)
- noble gases ( last column)
- inner transition metals (the ones separated)
alkali metals
- group 1A
- silver colored, soft, low density metals
- chemically highly reactive, rarely found in elemental form in nature
- reacts strongly with water to form base-alkali metal
Alkali Earth Metals
- Group 2A
- harder, higher melting, and denser than alkali metals
- reactive, but less than corresponding alkali metal
- form stable, insoluble oxides from which they are normally extracted
- oxides are basic - alkaline earth
Group 7A: Halogens
- chemically highly reactive
- found in nature only in compounds or as ions
- the elemental forms are made in laboratory
- each element exist as diatomic molecules
- only group exhibiting all 3 states at room temperature:
- F2, Cl2 = gas
- Br2 = liquid
- I2 = Solids
Group 8A Noble gas
- chemically very stable
- rarely react with other elements
- exist in nature as odorless, colorless monoatomic gases
different parts of periodic table which are located at different parts
- metals
- non metals
- metalloids
metals
- left side of zigzag
- except Helium (non metal)
- shiny, ductile, malleable
- good conductor
- high melting points
- high density
metalloids
- zigzag border separating metals and non metals
- blue-gray, shiny
- brittle, easily shattered
- poor conductor
- medium melting points
- medium density
nonmetals
- right of zigzag point
- dull
- brittle, easily shattered
- poor conductor
- lower melting points
- lower density
physical state of elements
liquid
Mercury and Bromine
proton
charge of +1
mass of 1 amu
in nucleus
neutron
charge of 0 or neutral
mass of 1 amu
located in nucleus
electron
electrical charge of -1
mass of .0005 amu
located in: dispersed through out electron cloud; not in nucleus
amu
atomic mass unit
atomic number of an element
Z
- ID # of the element
- number of the proton
what is an element
pure substance in which all atoms present have the same atomic number
Z
of both p+ and e-
isotopes
atoms of the same element with different numbers of neutrons (mass of an atom)
- same element with different mass
- same number of electrons
- same chemical properties
mass number
symbol A
A = p+ + nº
isotope symbol
A E Z A= mass E = atomic symbol Z = electron
weighted average mass
- the observed atomic mass for an element is the weighted average mass, based on the weight of each individual isotope
