i. subatomic particles (p.113 - 114). particlesymbollocationchargerelative mass (amu) actual mass...
TRANSCRIPT
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
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
Atomic number = # of protons in an atom Whole number shown on periodic table Periodic table is arranged by atomic number
The average atomic mass is the number at the bottom of this square
Found by averaging the natural abundances of its isotopes
Weighted average
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...
mass # = protons + neutrons
always a whole number
NOT on the Periodic Table!
© Addison-Wesley Publishing Company, Inc.
Atoms of the same element with different numbers of neutrons
C126
Mass #
Atomic #
Isotope notation:
Isotope name: carbon-12
Element name Mass #
Chlorine-37◦ atomic #:
◦ mass #:
◦ # of protons:
◦ # of electrons:
◦ # of neutrons:
17
37
17
17
20
Cl3717
Isotope notation:
Most elements are found as mixtures of isotopes
Relative abundance of each isotope is the same in each source
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
weighted average of all isotopes on the Periodic Table round to 2 decimal places
100
(%)(mass(mass)(%) )
Avg.AtomicMass
Avg.AtomicMass
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