Download 4-2: Structure of the Atom

4-1: ATOMIC STRUCTURE (page 104-110)
 Atoms are made up of 3 types of subatomic particles:
 _________________—positively charged, mass of about 1 a.m.u., located
in the nucleus.
 _________________—have no charge, mass of about 1 a.m.u., located in
the nucleus.
 _________________—negatively charged, very small mass—about 1/1800
the mass of a proton, located in the electron cloud around the outside of
the nucleus.
 The Nucleus
 The small, dense, _____________ charged center of the atom.
 Contains _______________ and _______________.
 Contains 99.9% of the atom’s mass.
 About 1/100,000 the size of the entire atom. (Think of a _________ in
the center of a football stadium!)
 Outside the Nucleus

Danish scientist Niels Bohr said that electrons moved in set paths around
the nucleus, similar to the way the ___________ orbit the ________.

Later, scientists said that instead of being in definite paths around the
nucleus, there were locations where electrons were likely to be found. This
region is called the ___________ ___________.

Within the electron cloud, electrons with different amounts of energy exist
in different __________ __________.

Within each energy level, electrons are most likely to be found in regions
called ___________. There are four different kinds of ___________:
____, ____, ____, and ____. The simplest kind (“s”) has a shape like a
____________.

An electron in the outermost energy level of an atom is called a
___________ ____________. These ____________ electrons
determine the chemical properties of the atom.
4-2: A Guided Tour of the Periodic Table (page 111-119)
 Periodic Law—states that the repeating _____________ and ____________
properties of elements change periodically with the elements’ ___________
____________.
Examples:

̶
Copper, silver and gold are all in the same vertical column on the periodic table. These
elements have similar properties: all are good conductors of heat and electricity, all
are malleable.
̶
He, Ne, Ar, Kr, Xe and Rn are all gases at room temperature, they do not react with
other substances easily.
 Horizontal rows on the periodic table are called _____________. The number
of protons and electrons in the elements increases by one as you move from
left to right across one of these rows.

Example: Going from left to right in the 4th period, K has 19 protons and
electrons; Ca has 20 protons and electrons, etc.
 Vertical columns on the periodic table are called ______________ or
_____________. Atoms of elements in the same vertical column have the
same number of ____________ _____________, and so these elements also
have similar _______________ ________________.

Example: Going down group 17: F, Cl, Br, I, and At all have 7 ___________
____________.
 Atomic Number—the number of ____________ in an atom’s nucleus.
 The symbol used to represent atomic number is ______.
 All atoms of a particular element have the same atomic number.
 Examples:
 All hydrogen atoms have __ ___________ in their nucleus, and thus have an atomic
number of 1.
 All _________ atoms have 82 protons in their nuclei, and thus have an atomic number
of 82.

Typically, the number of protons in an atom equals the number of electrons in
the atom. Therefore, we say that atoms are ________________ charged.

Atoms are considered to be chemically stable when they have their valence
shell completely full of electrons. Atoms can gain, lose, or share their
electrons in order to get a full valence shell. When an atom either gains one or
more electrons or loses one or more electrons, the atom is no longer neutrally
charged. When an atom or a group of atoms has either a negative or a positive
charge it is called an _________.
 Isotopes—atoms of an element that have the same number of protons as
another atom of that element, but have a different number of ____________.
 Example—isotopes of hydrogen:
protons--white
Protium Nucleus
neutrons--grey
Deuterium Nucleus
H-1
Tritium Nucleus
H-2
H-3
 Mass Number and Average Atomic Mass

___________ ________ ________ (amu)—unit used to measure the
masses of subatomic particles.
 Mass Number—the sum of the ____________ and ___________ in an
atom’s nucleus.
Remember: this means ADD them!!
 Mass number is always a whole number!!
 Examples:
 One isotope of carbon has 6 protons and 6 neutrons in the nucleus. Its mass number is
12 (6 + 6 = 12)
 Another isotope of carbon has 8 neutrons in the nucleus. What is its mass number?
 An atom of some element has 11 protons and 13 neutrons in the nucleus. What is the
element? ______________
What is its mass number? _________
 Average Atomic Mass—the weighted ____________ of the masses of the
naturally occurring isotopes for an element. This is the number that
appears on the periodic table in each element’s block.
 Average atomic mass is usually not a whole number.
 Example: the average atomic mass for: Mg is _____ amu; B is ______ amu
4-3: Families of Elements (page 120- 128)
 Elements are classified into 3 groups:
• Metal (define it)—

Where are metals found on the periodic table?

List 5 examples of metals.
• Nonmetal (define it)—

Where are nonmetals found on the periodic table?

List 5 examples of nonmetals.
• Semiconductors also known as ______________ (define it)—

Where are semiconductors found on the periodic table?

List the 6 semiconductors your book mentions on pg. 127.
 METALS—there are 3 categories of metals:
• __________ ___________—these metals are found in Group 1.
 List the elements in this category.
 List a few physical and chemical properties of elements in this category.
 How many valence electrons do the elements in this category have?
• ____________ _________ __________—these metals are found in
Group 2.
 List the elements in this category.
 List a few physical and chemical properties of elements in this category.
 How many valence electrons do the elements in this category have?
• _______________ _________—one of the elements found in Groups 3-12
 List 5 of the elements in this category.
• Some elements, such as technetium and promethium are ____________.
 Non-Metals
• _____________ —these non-metals are found in Group 17.
 List the elements in this category.
 List some physical and chemical properties of elements in this category.
 How many valence electrons do the elements in this category have?
• ____________ __________ —these non-metals are found in Group 18.
 List the elements in this category.
 List some physical and chemical properties of elements in this category.
 Why are elements in this group unreactive?
 How many valence electrons do most elements in this category have?
 Semi-Conductors
• What is the main use of semi-conductors?
4-4: Using Moles to Count Atoms (pg. 129-134)
 Mole (define it)—
 List some other counting units (other than the mole) that you know of:
 How many individual items are in each of the counting units you listed
above?
 How many individual items are in one mole?
 What is this number called?
 Molar Mass (define it)—

Example: The molar mass of silver is 107.8682 g/mol.
 Use a periodic table to find the molar masses of the following elements:
Ca
Cu
Xe
Be
Ba
 An element’s molar mass can be used as a conversion factor to convert moles to grams
or grams to moles.
 Example: What is the mass of 2.7 moles of neon gas?
2.7 mol Ne
20.1797 g
1
1 mol Ne
= 54.49 g Ne
 How many moles of mercury are in 150 g of Hg?
150 g Hg
1 mol Hg
1
200.59 g Hg
= 0.7478 mol Hg
Do the “Practice” problems on pg. 133 and the “Math Skills”
problems on pg. 134 of your textbook.
STUDY FOR YOUR TEST ON CHAPTER 4!!!