Warmup Draw an atom
2.1 Element Math
Atom Anatomy Protons positive charge particle mass = 1 amu or 1.67 x 10-24 g found in nucleus protons = atomic number Electrons negative charge particles mass = 0 amu or 9.11 x 10-28 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
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
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
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?
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
Sample Problem Isotope Abundance % Mass (amu) Chlorine-35 77.5 35 22.5 37