ch. 4.2 - atomic structure i. subatomic particles (p.113 - 114)
TRANSCRIPT
Ch. 4.2 - Atomic Structure
I. Subatomic Particles(p.113 - 114)
Subatomic Particle Properties
Particle Symbol Location Charge Relative Mass (amu)
Actual Mass (g)
electron
proton
neutron
e-
p+
n0
Electron cloud
nucleus
nucleus
–
+
0
1/1840
1
1
9.11 x 10-28
1.67 x 10-24
1.67 x 10-24
approx 0
Symbols
Elements are listed by their chemical symbols
Symbols are usually either one capital letter like C for Carbon, or one capital and one lowercase letter like Ne for Neon
Periodic Table
The periodic table gives much information we need to learn more about the atom of each element
Atomic Number
Atomic number = # of protons in an atomWhole number shown on periodic tablePeriodic table is arranged by atomic
number
Atomic Mass
The average atomic mass is the number at the bottom of this square
Found by averaging the natural abundances of its isotopes
Weighted average
Atom Math
Atomic Number
Symbol
Element Name
Atomic Mass
Atom Math
Protons Electrons
Protons Neutrons
# n0 = Atomic mass – Atomic number
Subatomic Particles
POSIT IVECHARG E
PROT ONS
NEUT RALCHARG E
NEUT RONS
NUCLEUS
NEG AT IVE CHARG E
ELECT RONS
AT OM
Most of the atom’s mass.
NUCLEUS ELECTRONS
PROTONS NEUTRONS NEGATIVE CHARGE
POSITIVE CHARGE
NEUTRAL CHARGE
ATOM
QUARKS#n0 = Atomic mass- Atomic #
equal in a neutral atomAtomic Number
equals the # of...
Subatomic Particles
Quarks component of
protons & neutrons
6 types
3 quarks = 1 proton or 1 neutron
He
Ch. 4.3 - Atomic Structure
II. How Atoms Differ (p. 114 - 121) Mass Number Isotopes Relative Atomic Mass Average Atomic Mass
A. Mass Number
mass # = protons + neutrons
always a whole number
NOT on the Periodic Table!
© Addison-Wesley Publishing Company, Inc.
B. Isotopes
Atoms of the same element with different numbers of neutrons
C126
Mass #
Atomic #
Isotope notation:
Isotope name: carbon-12
Element name Mass #
B. Isotopes
© Addison-Wesley Publishing Company, Inc.
B. Isotopes
Chlorine-37 atomic #:
mass #:
# of protons:
# of electrons:
# of neutrons:
17
37
17
17
20
Cl3717
Isotope notation:
Natural Abundances of Isotopes
Most elements are found as mixtures of isotopes
Relative abundance of each isotope is the same in each source
C. Relative Atomic Mass
12C atom = 1.992 × 10-23 g
1 p = 1.007276 amu
1 n = 1.008665 amu
1 e- = 0.0005486 amu
© Addison-Wesley Publishing Company, Inc.
atomic mass unit (amu)
1 amu = 1/12 the mass of a 12C atom
D. Average Atomic Mass
weighted average of all isotopeson the Periodic Tableround to 2 decimal places
100
(%)(mass(mass)(%) )
Avg.AtomicMass
Avg.AtomicMass
D. Average Atomic Mass
EX: Calculate the avg. atomic mass of oxygen if its abundance in nature is 99.76% 16O, 0.04% 17O, and 0.20% 18O.
100
(18)(0.20)(17)(0.04))(16)(99.76 16.00amu
Avg.AtomicMass
D. Average Atomic Mass
EX: Find chlorine’s average atomic mass if approximately 8 of every 10 atoms are chlorine-35 and 2 are chlorine-37.
100
(37)(20)(35)(80)35.40 amu