• The Atom• Atomic Number • Mass Number• Isotopes• Elements• Periodic Table
Atoms and Elements
What do all of these things have in common?
What Are Atoms?
• Atoms are the building blocks of matter.
• So what is “matter”?• Anything that has mass AND takes up
space.
Which of the following are considered matter
• Pizza• Wood• Love• Soil• Heat• Hope
• Air• Silk• Beauty• Juice• X- Rays• Sunshine
Subatomic Particles: Smaller Parts of an Atom
Particle Symbol Charge
Electron e- -1
Proton p+ +1
Neutron n 0
Location of Subatomic Particles
10-13 cm
electrons
protons
neutrons
10-8 cm
nucleus
Number of Electrons
An atom is neutral = zero net charge because the # of protons = # of electrons
Atomic Mass = # of p+ + # of nAtomic Number = # of protons = # of
electronsAn atom with a charge is
called an ion (unequal #’s of protons and electrons).
Electron Levels (Shells)
Contain electrons that are similar in energy and distance from nucleus
Low energy electrons are closest to the nucleus
Identify by letters k, l, m, n, o, p, q
The first shell (k) is lowest in energy, 2nd level next and so on k<l<m<n<o<p<q
Order of Electron Filling
The smallest shell must be filled before the next size can contain any electrons.
K-Shell 2 electrons L-Shell 8 electrons
M-Shell 8 electrons
Order of filling for the first 16 electrons
Shell k l m2e 8e 6e
Atomic Number
Counts the number of
?in an atom
Atomic Mass
Counts the number of
? + ?in an atom
Subatomic Particles in Some Atoms
16 31 65 O P Zn
8 15 30
8 p+ 15 p+ 30 p+
8 n 16 n 35 n8 e- 15 e- 30 e-
Which number do you think is the atomic number? How do you know?
What Are Isotopes?
Atoms with the same number of protons,
but different numbers of neutrons.
Atoms of the same element (same atomic number) with different atomic masses.
Isotopes of Chlorine
35Cl 37Cl17 17
chlorine - 35 chlorine - 37
Learning Check
Naturally occurring carbon consists of three isotopes, C-12, C-13, and C-14. State the number of protons, neutrons, and electrons in each of these carbon atoms.
12C 13C 14C 6 6 6
#p _______ _______ _______
#n _______ _______ _______
#e _______ _______ _______
What Are Elements?
Pure substances made up of all the same type of atom (same # of: p+, n, e-)
The 4 most abundant elements on Earth are carbon, oxygen, hydrogen, and nitrogen (POINTER: COHN or NOCH)
112 elements known todayExamples: carbon
goldcalcium
What element do these things have in common?
Here’s a Hint…
IRON (Fe) Latin: ferrum
• Cheapest…• Most common…• Most useful…
• Used extensively for the making of STEEL
IRON (Fe) Latin: ferrum
It also carries oxygen in hemoglobin in red blood cells.
Symbols of Elements
Use 1 or 2 letter abbreviations Capitalize the first letter only
Examples:C carbon Co cobaltN nitrogen Ca calciumF fluorine Br bromine
O oxygen Mg magnesium
Symbols from Latin NamesElement Symbol Latin nameCopper Cu cuprumGold Au aurumLead Pb plumbumMercury Hg hydrargyrumPotassium K kaliumSilver Ag argentumSodium Na natriumTin Sn stannum
% Major Elements in the Body
O 65.0 % K 0.34C 18.0 S 0.26H 10.0 Na 0.14N 3.0 Cl 0.14Ca 1.4 Fe 0.004P 1.0 Zn 0.003 Mg 0.50
Take a guess what the correct symbol is for the element!
Select the correct symbol for each:A. Calcium
1) C 2) Ca 3) CAB. Sulfur
1) S 2) Sl 3) SuC. Iron
1) Ir 2) FE 3) Fe
Take a guess what the correct element is! Select the correct name for each:A. N
1) neon 2) nitrogen 3) nickelB. P
1) potassium2) phogiston3) phosphorus
C. Ag1) silver 2) agean3) gold
Atomic Theory
Atoms are the building blocks
of all matter, which included
elements
Similar atoms in each element
Different from atoms of other
elements
Periodic Table
The periodic table is an arrangement of the elements according to:
•The number of protons, neutrons, and electrons
•The way they look•The way they act
The Periodic Table
Shows the mass number and atomic
number
Gives the symbol of the element
mass number
23 Na
atomic number 11
Groups of Elements
Vertical (up and down) columns
on the periodic table
Indicates the number of
electrons on the outer most shell
called valence electrons.
Periods on the Periodic Table
Horizontal (left to right) rows on the
Periodic Table.
Numbered 1-7
Indicates the number of
orbitals or shells the element
has.
Periods on the Periodic Table
123456
Using The Periodic Table
• In your notes, use your periodic tables to determine the following for the elements at the bottom.• The number of protons• The number of neutrons• The number of shells• The number of electrons on the outer most shell
(valence electrons)• Draw the atoms for each
Calcium (Ca), Magnesium (Mg), Chlorine (Cl)
