Download atoms

Structure of Matter
Create a foldable from the reading
Atoms Foldable-
important informational
notes from the reading , “ What Makes Up Matter”
AtomsMatter –anything having mass or volume
Made of tiny building blocks “atoms”, small, invisible
Nucleus tiny compared to entire size of atom
# of electrons = # protons making atoms on periodic table of
elements stable, neutral, balanced element atoms
Atomic Mass # is the # protons + # neutrons in nucleus
Atoms of the same type of element called isotopes, have
different # of neutrons
Atoms fill their outer energy levels
Lewis dot diagrams show outer most energy levels or
Ne
valence electrons
Nucleus
• Most of the mass of an atom
• Center of the atom
• Contains neutrons & protons
Not similar to nucleus of a cell.
Protons•
•
•
•
•
Subatomic particle in nucleus of atom
Positive electromagnetic charge
About the same mass as a neutron
# of protons identifies the atom= atomic number
Protons are part of the atomic mass of atom
Neutrons
•
•
•
•
•
Subatomic particle in the nucleus of atom
No electrical charge, neutral
About the same mass as a proton
Part of the atomic mass of the atom
Neutron # is different in isotopes
Electrons
•
•
•
•
•
•
•
•
•
Move around space outside of nucleus
Negative electromagnetic charge
Have very little mass 1836 x lighter than protons
Unpredictably move in space around outside of
nucleus “electron cloud”
Distance from nucleus depends on amount of energy
Energy levels, shells=positions of electrons from
nucleus (closer to nucleus lower energy, farther
away more energy)
Energy levels hold certain # of electrons
Valence electrons= outer most energy level electrons
Atoms gain, share, or lose electrons with other atoms
What is Atomic Number?
16
S
Sulfur
Atomic Number is the number of
protons in an atom. The periodic
table of elements is arranged by
proton number & atomic mass
number
What are symbols for elements?
•
16
Symbols are usually the capital letters of the
first letter of the name of the element
symbol
S
Sulfur
• Some element symbols are a
Capital letter and a lower case
letter like Ca for Calcium
• Others are have symbols for
their Latin or Greek names like
Pb Lead which means Plumbum
in Latin.
Elements are named for places, persons, or things.
What is the Atomic Mass Number?
3
Li
Lithium
6.94
The atomic mass number tells
the protons plus neutron
mass in the nucleus
Atomic mass # rounds to 7- there
are 3 protons in the nucleus and 4
neutrons (each weighing 1 atomic
mass unit = 7 amu)
Read the table from left to right. Least protons on top left corner, lighter elements on top left corner of table.
Most Protons and heaviest elements on lower right corner of table.
Families are columns and have similar properties & valence electrons
Periods are rows and have similar number of energy levels.