1. Warmup
Draw an atom

2. 2.1 Element Math

3. Atom Anatomy Protons positive charge particle
mass = 1 amu or 1.67 x g
found in nucleus
protons = atomic number
Electrons
negative charge particles
mass = 0 amu or 9.11 x g
found outside the nucleus
in a neutral atom, electrons = protons
Neutrons
zero charge particle
mass = 1 amu (same as proton)
found in nucleus
neutrons = mass number - atomic number

4. Ion-atom with a charge, gained or lost electrons
Isotope- same element different number of neutrons
Atomic Mass- The weighted average mass of the atoms in a naturally occurring sample of the element
Nucleon- Any particle in the nucleus
Valence Electron- outer energy level electron

5. Finding Subatomic Particles
Charge 96 2+ Mo 42
Atomic Number = # of protons
Mass Number = # of protons + # of neutrons
Neutrons = Mass number – Atomic number
Charge = # of Protons - # of Electrons
Electrons = # of protons in a neutral atom

6. Sample Problems 1. How many protons and neutrons
are present in an oxygen atom?
2. Write the symbol for the ion with
9 protons, 10 neutrons, and 10 electrons.
3. How many protons, neutrons, and electrons
are present in the 5626Fe2+ ion?

7. Average Atomic Mass Must know abundance and mass of each isotope.
Mass (amu)
Boron-10 19 10
Boron-11 81 11
Boron-10
0.19 × 10=
1.9
Boron-11
0.81 × 11=
+ 8.91
Total →
10.81

8. Sample Problem Isotope Abundance % Mass (amu) Chlorine-35 77.5 35
22.5 37