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Chapter 4 Lesson 3
Periodic Table
Materials Needed Today
Please take these materials out of your backpack.
•Pencil
•Blank sheet of paper for notes.
Hot Sync Monday 1/13/14
Answer the following questions in complete sentences on the hot sync worksheet.
Write out and choose which one is correct to finish the following sentence:
An atom is best described as…. • protons and electrons grouped together
in a random pattern • protons and electrons grouped together
in an alternating pattern • a core of protons and neutrons
surrounded by electrons • a core of electrons and neutrons
surrounded by protons
JOKE OF THE DAY
In N Out
shake
waiter
element
atomic number
mass number
isotope
average atomic mass
ion
4.3 Elements, Isotopes, and Ions—How Atoms Differ
Carbon
6
C 12.011
Determined by
the number of
protons.
Is the number of
protons in the
nucleus.
The number of
protons PLUS
Neutrons in the
nucleus
Atomic Number and the Periodic Table (cont.)
4.3 Elements, Isotopes, and Ions—How Atoms Differ
Increasing atomic number
Isotopes
• Atoms of the same element that have different numbers of neutrons are called isotopes.
4.3 Elements, Isotopes, and Ions—How Atoms Differ
Isotopes (cont.)
• The average atomic mass of an element is the weighted average mass of the mixture of an element’s isotopes.
4.3 Elements, Isotopes, and Ions—How Atoms Differ
Isotopes (cont.)
• Radioactive isotopes are unstable and break down releasing particles, radiation, and energy.
4.3 Elements, Isotopes, and Ions—How Atoms Differ
Positive Ions— Losing Electrons
• An atom that has gained or lost an electron and is no longer neutral is called an ion.
• When an atom loses an electron, it has more protons than electrons.
• The atom has a positive charge and is called a positive ion.
4.3 Elements, Isotopes, and Ions—How Atoms Differ
Negative Ions— Gaining Electrons
• When an atom gains an electron, it has more electrons than protons.
• The atom has a negative charge and is called a negative ion.
• Positive ions and negative ions attract each other and form compounds.
4.3 Elements, Isotopes, and Ions—How Atoms Differ
Lesson 3 Review
The carbon element has several isotopes. How is carbon-14 different from carbon-13?
A Carbon-14 has a positive charge.
B Carbon-13 has a positive charge.
C Carbon-14 has one more neutron than carbon-13.
D Carbon-14 has one less neutron than carbon-13.
4.3 Elements, Isotopes, and Ions—How Atoms Differ
A B C D
0% 0%0%0%
1. A
2. B
3. C
4. D
Lesson 3 Review
What is the number of protons in an element called?
A isotope
B atomic number
C atomic mass
D radiotope
4.3 Elements, Isotopes, and Ions—How Atoms Differ
A B C D
0% 0%0%0%
1. A
2. B
3. C
4. D
Lesson 3 Review
How does a neutral atom become a negative ion of the same element?
A It gains a proton.
B It loses a proton.
C It loses an electron.
D It gains an electron.
4.3 Elements, Isotopes, and Ions—How Atoms Differ
A B C D
0% 0%0%0%
1. A
2. B
3. C
4. D
