I. Subatomic Particles (p.113 - 114) Ch. 4.2 - Atomic Structure I. Subatomic Particles (p.113 - 114)
Subatomic Particle Properties Symbol Location Charge Relative Mass (amu) Actual Mass (g) e- Electron cloud 1/1840 electron – 9.11 x 10-28 approx 0 p+ + proton nucleus 1 1.67 x 10-24 n0 neutron nucleus 1 1.67 x 10-24
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 atom Whole number shown on periodic table Periodic 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 # n0 = Atomic mass – Atomic number Protons Electrons Protons Neutrons # n0 = Atomic mass – Atomic number
Subatomic Particles equal in a neutral atom #n0 = Atomic mass NUCLEUS ELECTRONS equal in a neutral atom PROTONS NEUTRONS NEGATIVE CHARGE QUARKS #n0 = Atomic mass - Atomic # Atomic Number equals the # of... POSITIVE CHARGE NEUTRAL CHARGE Most of the atom’s mass.
Subatomic Particles Quarks He component of protons & neutrons 6 types 3 quarks = 1 proton or 1 neutron
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 © Addison-Wesley Publishing Company, Inc. always a whole number NOT on the Periodic Table!
Mass # Atomic # B. Isotopes Atoms of the same element with different numbers of neutrons Isotope notation: Mass # Atomic # Element name Mass # Isotope name: carbon-12
B. Isotopes © Addison-Wesley Publishing Company, Inc.
B. Isotopes Isotope notation: Chlorine-37 atomic #: mass #: # of protons: # of electrons: # of neutrons: 17 37 20
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 atomic mass unit (amu) 1 amu = 1/12 the mass of a 12C atom 1 p = 1.007276 amu 1 n = 1.008665 amu 1 e- = 0.0005486 amu © Addison-Wesley Publishing Company, Inc.
D. Average Atomic Mass Avg. Atomic Mass weighted average of all isotopes on the Periodic Table round to 2 decimal places Avg. Atomic Mass
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. Avg. Atomic Mass 16.00 amu
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. Avg. Atomic Mass 35.40 amu