Periodic table 5

1. Periodic table 5 Isotopes pp 116-119

2. Review of Atomic Structure • Nucleus • Protons have a positive (+1) charge • Neutrons have no charge • Electrons • Electrons have a negative (-1) charge • Much smaller mass • Located outside the nucleus

3. Protons • When you change the number of protons, you change the element. • The atomic number (Z) is the whole number on the periodic table. • Hydrogen Z = 1 • Calcium Z = 20 • What is the atomic number of Silicon? • Oxygen? • How many protons does Magnesium have?

4. Electrons • A neutral atom has the same number of electrons as protons. • Z x (+1) + Z x (-1) = 0 • When an atom gains or looses electrons, it has a charge. It is called an ion. • The monatomic ion forms based on its valence. • They want the “easiest” way to have 8 in its outer shell. • The valence of Sodium (Na) is 1. What Ion will it form?

5. Neutrons • All atoms of the same element will have the same number of protons. (atomic number, Z) • Atoms of the same element may have a different number of neutrons. • If you change the number of neutrons, you change the: • massnumber of the element • The isotope of the element

6. Vocabulary • Mass Number – the number of protons plus the number of neutrons • Isotope – an atom that has the same number of protons but a different number of neutrons

7. Isotopes of Hydrogen

8. Isotope Symbols

9. Isotopes of Carbon