3. Periodic Table
Atoms make up all matter
Elements are any material that is made up
of only one type of atom
Elements are organized onto the periodic
table
4. Each element is designated an atomic
symbol on the periodic table
9. Why don’t we pass through one another?
Electrical repulsion – two electrons with
negative charges will repel each other
10. Protons
Protons and neutrons are bound to the
atomic nucleus
Protons carry a positive charge
Protons are identified by Atomic number
atom is electrically neutral: Number of
protons = number of electrons;
11. Neutrons
Neutron has no electrical charge, but the
same mass as a proton
Protons and neutrons are called nucleons
Mass given to each proton and neutron is 1
12. Atomic Mass
• Electrons are so small they are
considered negligible in mass
• Atomic mass is measured in the unit –
amu
Atomic Mass Unit
Atomic mass on the periodic table
14. Electrons are so small they are
considered negligible in mass
Protons and neutrons in the nucleus
• Atomic mass is measured in the unit –
amu
Atomic Mass Unit
15. Atomic Mass
Atomic mass on the periodic table –
average of all its isotopes
Isotope – an Element with differing
number of neutrons
16. Mass Number
Mass number = total number of protons
and neutrons
Identify isotopes by the mass number
17. Agenda Bell work
• Finish yesterday’s WS
• Finish notes
• Practice Isotopes and • Distinguish between the
Ions following:
– Atomic Number
– Mass Number
• History of the Atom
– Atomic Mass
• Atoms Quiz tomorrow •
Define an Isotope
• What identifies what an
element is?
18. Writing Isotopic Symbols
X = element symbol
A = Mass Number
Z = Atomic Number
Total number of neutrons:
Mass Number – Atomic number = number of
neutrons
