1. I. Subatomic Particles (p.113 - 114)
Ch Atomic Structure
I. Subatomic Particles
(p )

2. 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

3. 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

4. Periodic Table
The periodic table gives much information we need to learn more about the atom of each element

5. Atomic Number Atomic number = # of protons in an atom
Whole number shown on periodic table
Periodic table is arranged by atomic number

6. 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

7. Atom Math
Atomic Number
Symbol
Element Name
Atomic Mass

8. Atom Math # n0 = Atomic mass – Atomic number Protons Electrons Protons
Neutrons
# n0 = Atomic mass – Atomic number

9. 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.

10. Subatomic Particles Quarks He component of protons & neutrons 6 types
3 quarks = 1 proton or 1 neutron

11. Ch. 4.3 - Atomic Structure II. How Atoms Differ (p. 114 - 121)
Mass Number
Isotopes
Relative Atomic Mass
Average Atomic Mass

12. A. Mass Number mass # = protons + neutrons always a whole number
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always a whole number
NOT on the Periodic Table!

13. 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

14. B. Isotopes
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15. B. Isotopes Isotope notation: Chlorine-37 atomic #: mass #:
# of protons:
# of electrons:
# of neutrons: 17 37 20

16. Natural Abundances of Isotopes
Most elements are found as mixtures of isotopes
Relative abundance of each isotope is the same in each source

17. 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 = amu 1 n = amu 1 e- = amu
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18. D. Average Atomic Mass Avg. Atomic Mass
weighted average of all isotopes
on the Periodic Table
round to 2 decimal places
Avg.
Atomic
Mass

19. 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

20. 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