Bellringer

1
Bellringer

1. Who is credited with the development of the
   periodic table?
2. What is the difference between Mendeleevs
   version of the periodic table and the current
   version of the periodic table?

2
How Atoms Differ

• Objectives
• 3.2 Calculating the number of protons, neutrons,
  and electrons in an isotope

3
Atomic Number

• Def. the number of PROTONS in an atom
• What is the atomic number of
• Hydrogen?
• Lead?
• Chlorine?
• How many protons are in an atom of
• Hydrogen?
• Lead?
• Chlorine?

4
Atomic Number (cont.)

• What is the charge of a proton?
• Where are protons found?
• What else is in the nucleus?
• What would be the charge of the NUCLEUS of the
  following elements
• Hydrogen?
• Lead?
• Chlorine?

5
Atomic Number (cont.)

• What is needed to BALANCE this positive nuclear
  charge, so the atom is neutral?
• So how many electrons
• Atomic number number of protons number of
  electrons
• How many electons are in an atom of
• Hydrogen?
• Lead?
• Chlorine?

6
Practice Assignment

• P.99 11-13
• Study Guide workbook p.21 (1-12)