section ii: basic building materials
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COMPOSITION OF MATTER ALL MATTER IN THE UNIVERSE IS AN ELEMENT OR IS MADE OF SOME COMBINATION OF ELEMENTS!TRANSCRIPT
UNIT I: ALCHEMYSECTION II: BASIC BUILDING MATERIALS
COMPOSITION OF MATTER
ALL MATTER IN THE UNIVERSE IS AN ELEMENT OR IS MADE OF
SOME COMBINATION OF ELEMENTS!
ELEMENT Element- a unique substance that cannot
be broken down into simpler substances through chemical processes.
Elements are the building blocks of matter. Elements are found on the periodic table. The first letter of an element’s symbol is
ALWAYS uppercase and if there is a second letter it is ALWAYS lowercase.
EX.
COMPOUNDS Compounds- a pure substance that is a
chemical combination of two or more elements in a fixed ratio.
Compounds are represented by chemical formulas.
Compounds can be broken down into simpler stable substances.
Ex.
CHEMICAL FORMULAS Chemical Formula- a combination of
symbols and subscripts that indicates the number and types of elements in a compound.
Ex. CuSO4
Ex. Li2S
Ex. NaCl
Phases of Matter Matter can come in different physical
forms called phases.
Phase- the physical form a substance is in, such as solid, liquid, or gas.
Phases are influenced by temperature.
Solid (s), liquid (l), gas(g)
Aqueous Aqueous- a substance that is dissolved
in water. Aqueous (aq)
What is the difference between Nacl(l) and NaCl(aq)?
Chemical Change Chemical Change- a change in which one
or more substances change into entirely new substances with different properties.
Examples:
Chemical Reactions
Chemical reaction- process by which one or more substances change to produce one or more different substances.Examples:
What are some indicators that chemical reaction has taken
place?
•Precipitate Formation
•Odor
•Release/Absorption of Energy
•Bubbles/Gas Production
Products & Reactants
Reactants-substances that exist prior to a chemical reaction.
Products- substances that are formed as a result of a chemical reaction.
carbon + oxygen carbon dioxide C (s) + O2 (g) CO2(g) reactants productCarbon reacts with oxygen to form/to yield carbon dioxide.
Basic Laws of Matter Law of Conservation of Mass- mass is
neither created or destroyed during ordinary chemical reactions or physical changes.
A + B → AB 1mu 3mu 4mu
Antoine Lavoisier
History of the Periodic Table
In 1869, Dmitri Mendeleyev’s published the first periodic table.
Mendeleev arranged the elements horizontally by increasing atomic mass and placed elements in groups (vertically) based on similar properties.
History of the Period Table
Mendeleyev’s Periodic Table
History of the Periodic Table
Mendeleyev’s Periodic Table Mendeleev’s procedure left many holes
throughout the periodic table.
Mendeleyev was able to predict the properties of elements that would eventually fill those holes even though they were not discovered yet.
Ex. Ekasilicon- Germanium
Average Atomic Mass Average Atomic Mass- the mass of one
atom of a given element measure in atomic mass units (amu).
Located beneath the elements symbol on the periodic table.
Atomic mass units are extremely small units.
History of the Periodic Table
In 1913, Henry Moseley developed the Modern Periodic Table. He arranged periodic table in rows by increasing atomic number and in columns by similar properties.
History of the Periodic Table
Moseley’s Accomplishments: Discovered that the positive charge of the
nucleus increases from one element to the next.
Led to the modern definition of atomic number.
Moseley’s periodic table explained some of the contradictions that Mendeleev experienced within his model.
History of the Periodic TableEarly 1900’s
Moseley’s Periodic Table
Atomic Number Atomic Number- Number of protons in an
atom. Located above the elements symbol on
the periodic table.
Periodic LawPeriodic Law- states that the chemical & physical properties of the elements are periodic function of their atomic numbers.
Group/Family- vertical columns of elements on the periodic table with similar properties.
Periods- horizontal rows of elements on the periodic table arranged by increasing atomic number.
Metals, Nonmetals, & Metalloids
Metals Make up most of the periodic table. Ductile- can be drawn into wire Malleable- can be hammered into thin sheets. Lustrous- shiny Good Conductors of heat & electricity Located to the left of the step ladder on the
periodic table.
Metals, Nonmetals, & Metalloids
Nonmetals Brittle-break when hammered. Poor conductors of heat & electricity. Lack luster Located to the right of the step ladder on
the periodic table.
Metals, Nonmetals, & Metalloids
Metalloids Semimetals. Properties of both metals & nonmetals. Located along the step ladder on the
periodic table. Examples: B, Ge, Sb, Te, At, Si, As, Po
Metals, Nonmetals, & Metalloids
Alkali Metals- Group 1A
Most reactive group of metals.
Usually found in combined form as a salt due to their high reactivity.
Combine vigorously with nonmetals especially groups 6A & 7A .
React readily with water. Soft and silvery appearance.
Alkaline Earth Metals- Group 2A
Found in the earth’s crust but not in the elemental form due to their high reactivity. They are usually found in rock structures.
2nd most reactive group of metals. More dense than group 1. Shiny silvery-white color.
Transition Metals- Groups 1B-8B
Typical metallic properties.
Good conductors. Lustrous. Produce colored
ions.
Main Group Elements Groups 1A-8A
Properties of elements vary greatly. Contains all of the nonmetals & metalloids
as well as some metals.
Halogens -Group 7A
Most reactive groups of non-metals. React vigorously with metals (especially
groups 1A & 2A) to produce salts. Fluorine is a poisonous pale yellow gas,
chlorine is a poisonous pale green gas, bromine is a toxic and caustic brown volatile liquid, and iodine is a shiny black solid which easily sublimes to form a violet vapor on heating.
Found in nature in the combined state.
Noble Gases- Group 8A
Least reactive of all elements. Often called inert gases. All are gases. The noble gases are all found in
minute quantities in the atmosphere, and are isolated by fractional distillation of liquid air.
Inner Transition Metals- Periods 6 & 7
Lanthanides (Period 6)- Rare Earth Metals
Shiny reactive metals
Actinides (Period 7) Unstable & radioactive metals. Most are laboratory made.
Reactivity of Metals TrendPeriod Trend- Metals increase
in activity from right to left on the periodic table.
The alkali metals are the most reactive group of metals.
Group Trend- Metals increase in reactivity from top to bottom with a group.
Ra is the most reactive alkaline earth metal.
Reactivity of Nonmetals Trend
Period Trend- Nonmetals increase in activity from left to right on the periodic table with the exception of the noble gases.
The halogens are the most reactive group of nonmetals.
Group Trend- Nonmetals increase in reactivity from bottom to top with a group.
F is the most reactive halogen.
Reactivity TrendsWhat is the most reactive metal on the
periodic table? Explain.
Circle the most reactive nonmetal in each row:
1. Te Po S2. Br I Cl