Download CHAPTER6_MEET_THE_ELEMENTS

Chapter 6 Meet The Elements
6.1 Symbols for the Elements
Read p 192-197 Chemical Symbols and Formulas - answer questions on p. 197 1-6ab
Know how to complete chart on page 196
Know the symbols for the first 20 elements of the periodic table on p. 562
6.2 Elements on The Planet Earth Read p. 198-200
Questions:
1. What are the 4 main gases found in our atmosphere?
2. Why is photosynthesis vital for life on Earth?
3. What is the hydrosphere?
4. List one element and 4 compounds found in our hydrosphere?
5. What is the importance of dissolved 02 and CO2 in our hydrosphere?
6. List the four most common elements in the Earth’s crust.
7. Oxygen is the most abundant element in the Earth’s crust, yet the Earth’s crust is
solid. How is this possible?
8. Only a few metallic elements exist in nature in an uncombined state. List these
elements.
Different Kinds of Elements Read p. 203-204
Questions:
1. There are two main categories of elements and one category which lies in between
these. List these three categories of elements and give the general properties of each
group.
2. a) What does the term “malleable” mean?
3. b) What does the term “ductile” mean?
4. List 6 common metals and 6 common non-metals.
5. Why did it take so long for people to start using aluminum, even though it is the most
abundant metal in the Earth’s crust?
6.3 Metallurgy
Metallurgy is the study of metals- their properties, structure, refining from ores, alloys,
and formation of finished products. There are three main processes in metallurgy:
extraction, modification, and alloying.
Rarely are metals found lying around in chunks in nature. Instead, they are almost mixed
with other materials in compounds. This mixture, buried in rock is called a mineral and
if there is enough of the mineral present, to make it worthwhile to mine, the rock is called
an ore.
Extraction - is the mechanical and chemical processes used to remove metals from the
minerals and ores and that contain them. There are 2 main components of extraction:
1. Concentration – removing as much rock as possible, so that the remaining mixture
contains as much of the mineral as possible. This involves crushing and separating
the ore from the waste rock mixed with it.
2. Decomposition – is a process of breaking down the mineral compound by a chemical
change in order to obtain the metal in a nearly pure form. This is often referred to as
smelting.
Smelting involves mixing the concentrated mineral with chemical and adding heat or
electricity (electrolysis).
Modification - Altering the properties of a pure metal, without using a chemical change.
An example would heating and beating metal to make it tougher and harder. This process
is know n as tempering.
Alloying – mixing metals with one or more metals to produce a new metal with desirable
qualities.
Examples:
bronze (copper + tin)
yellow gold (gold + copper)
pewter (tin + lead + copper)
stainless steel (iron + carbon + nickel + chromium)
6.4 Families of Elements
Chemical Family – is a term used to describe a group of related elements. For example,
copper, silver and gold all belong to the same chemical family. These metals are often
referred to as the coinage metals, even though few countries use them to make new coins
today.
Complete Page 216 Science Inquiry Activity – Patterns of Properties in a Chemical
Family
The Periodic Table
The Periodic Table – is a table in which the elements are organised in rows or columns,
according to their atomic number and their patterns of similar properties.
Atomic number – is the number of protons in the nucleus of an atom. This number is
ABOVE the element’s symbol. An element’s position in the periodic table is determined
by it’s atomic number. The atomic number (number of protons) makes each element
unique from the others.
Vertical columns are called GROUPS. Families of elements with similar properties, such
as the coinage metals are located in the same group.
Horizontal rows are called PERIODS. The atomic number of elements increases as you
move from left to right across the table, starting with hydrogen (H) which has an atomic
number of 1.
Atomic Mass – is the mass of an average atom of an element. It also equal the total
number of protons and neutron in the nucleus of an atom.
Atomic Structure
Atoms – an atom is the smallest unit of matter that can take place in a chemical change.
The word comes from the Greek word Atomos which means indivisible.
All matter is made up of atoms.
Atoms are composed of protons, neutrons and electrons.
Protons have a positive electrical charge.
Neutrons have a neutral charge.
Electrons have a negative electrical charge.
Atoms have a nucleus which contain protons and neutrons and the electrons form a cloud
around the nucleus. These electrons move
Bohr-Rutherford model of atomic structure – (not the last word on atomic structure) can
be called the first “modern view” of an atom. It compares the nucleus of an atom to the
sun, and the electrons to the planets, which remain in their orbits revolving around the
nucleus. These orbits are called “electron shells”