Topic: Chemistry
Aim: Explain how elements are classified
in the Periodic Table of Elements.
Do Now: next slide
HW: Atoms, Elements, Compounds and
Mixtures Exam Review Sheet
Chromatography
Evaporation
Sieve
Filtration
Magnet
The substances in a mixture can be
separated by physical means because
1. the substances are chemically combined.
2. the substances are chemically conded
together.
3. the substances are physically, not
chemically, mixed.
Sand and iron particles that are similar
in size and color are mixed together
in a beaker. What would be the best
method of separating the particles?
1. Use tweezers to separate them.
2. Add water to the mixture.
3. Use a magnet to separate them.
4. Pour the mixture into a filter.
A green plant contains the green pigment
chlorophyll. However, it also contains
other pigments such as carotene and
xanthophyll. How can these pigments
be separated from each other?
1. Use tweezers to separate them.
2. Use filtration to separate them.
3. Use chromatography to separate them.
4. Use a sieve to separate them.
How can you separate sugar from a sugar
water solution?
1. Use a magnet to separate the sugar from
the water.
2. Use filtration to separate the sugar from
the water.
3. Use chromatography to separate the
sugar from the water.
4. Use evaporation to separate the sugar
from the water.
How can you separate a solid from a
liquid mixture?
1. Use a magnet to separate the insoluble
substance from the mixture.
2. Use evaporation to separate the insoluble
substance from the mixture
3. Use filtration to separate the insoluble
substance from the mixture.
4. Use chromatography to separate the
insoluble substance from the mixture.
Periodic Table of Elements
• System of grouping elements and predict the
properties of elements
Element Key
Element name
Atomic number
(make sure you
leave space here)
Atomic symbol
Atomic Mass
Atomic number:
• # of protons
• Different for each element
• Never changes
Mass number
• Sum of protons and neutrons
• Round the atomic mass to
nearest whole number
Atomic number:
42
Atomic mass:
95.84
Mass Number:
96
Atomic number:
5
Atomic mass:
10.81
Mass Number:
11
How to determine the # of neutrons
• Subtract mass number and atomic number
Atomic number:
42
Mass Number:
96
# of neutrons:
96 – 42 =
54 neutrons
How many neutrons are
located inside an atom
of boron?
• Mass number
= 11
• Atomic number
=5
• Mass # - Atomic #
11 - 5
= 6 neutrons
Mass #
= 48
# of protons
= 22
48 – 22
= 26 neutrons
How are elements arranged?
• By Atomic number
• Increases as move from L  R
Columns
• Families or Groups
• Elements have SIMILAR BUT NOT
identical properties
• Ex: Family 1 (Alkali metals):
– are all soft, white, shiny metals
– highly reactive
• Ex: Family 2 (Alkaline Earth Metals)
– are less reactive than alkali metals
– highly reactive
– are shiny
Topic: Chemistry
Aim: Explain how elements are classified
in the Periodic Table of Elements.
Do Now: Take out your Periodic Table
notes.
HW: Phases Reading Notes due
Thursday.
• Atomic number:
= 35
• Mass number:
= 80
• Number of neutrons:
80 – 35
= 45 neutrons
• How many electrons
does Bromine have?
When Br is neutral, it
has the same number
of protons and
electrons.
35 electrons
42 protons 22 protons 5 protons
42 electrons22 electrons 5 electrons
Rows
• Periods
• Elements are NOT ALIKE in
properties
•
•
•
•
4 main categories of PT
Metals
Nonmetals
Metalloids
Noble Gases
Metals: 88 elements to left of zigzag
line
Nonmetals: to right of zigzag line
Metalloids: along both sides of the
zigzag line
Metalloids:
Boron, Silicon, Germanium, Arsenic,
Antimony, Tellurium, Polonium, Astatine
Noble Gases
• Group 18
• Inert gases
• He, Ne, Ar, Kr, Xe, Rn)
Noble gases glow brightly
when an electric charge is
passed through them, and
so are used as advertising
signs: neon tubes glow red,
xenon blue, and krypton
bluish-white; argon tubes
glow pale red at low
pressures, blue at high
pressures.
• 2 bottom rows: Rare Earth Elements
– Lanthanoid series: can be found naturally on Earth
– Actinoid series: radioactive and some not found in
nature
Let’s summarize…
1. Explain how the periodic table of elements
is arranged.
2. What does the decimal number in an
element key represent?
3. How do you determine the mass number?
4. How can you determine the number of
neutrons?
5. Identify the 4 categories of elements on
the periodic table.
NUMBER OF
NEUTRONS?
Mass #
= 112
# of protons
= 48
112 – 48
= 64 neutrons
Review:
1. Elements in the periodic table are
arranged by
2. atomic number
3. atomic weight
4. number of neutrons
5. chemical reactivity
2. Which of these things will you
NOT find in the periodic table?
1. Element symbol
2. Atomic weight
3. Atomic orbital radius
4. Atomic number
5. Which element is a metalloid?
1. S (Sulfur)
2. Si (Silicon)
3. Ba (Barium)
4. Br (Bromine)
Atomic number:
22
Atomic mass:
47.87
Mass Number:
48
How many protons? 2
How many electrons? 2
How many neutrons? 4-2 = 2
5. Volume is
a.the amount of matter in an object
b.the amount of space an object takes
up.
c.the gravitational pull on an object.
d.an object's resistance to a change in
motion.
3. A millimeter is equal to
a. 0.1m
b. 0.01m
c. 0.001m
d. 0.0001m
6. A liter of water contains
a.1000 mL.
b. 100 mL.
c. 10 mL.
d. 1 mL