1. SECTION 14-3 WHAT IS ATOMIC NUMBER?

2. ATOMIC NUMBER Atoms of different elements have different number of protons. This number is called the atomic number. No two elements have the same number. Atoms are neutral so the number of electrons equals the number protons

3. SECTION 14-4 WHAT IS ATOMIC MASS?

4. ATOMIC MASS The mass is very small. Measured in atomic mass units (amu). 1 amu = mass of proton = mass of neutron. Mass of electron = 1/1800 amu. Since mass of electron is so small, the atomic mass is the mass of the proton and neutron combined. Mass # – atomic # = # of neutrons

5. H.W P. 263 CHECK/APPLY 1-11 WKST. 14-3 ENRICHMENT 14-3 P. 263 SKILL BUILDER 1-5 P. 265 CHECK/APPLY 1-7 WKST. 14-4 P. 265 SKILL BUILDER A-E