1. Properties of Elements

2. Properties are the qualities that, taken together, are usually peculiar to an object. Properties are the qualities that, taken together, are usually peculiar to an object.

3. Properties of Elements Physical properties, such as: Physical properties, such as: Solid, liquid, or gas Solid, liquid, or gas Conducts electricity Conducts electricity Hardness Hardness Density Density Color Color Acid or base Acid or base Reactivity Reactivity

4. Grouping the Elements Groups (also known as Families). Similar due to same number of valence electrons. Groups (also known as Families). Similar due to same number of valence electrons.

5. Grouping the Elements Properties largely determined by valence electrons.

6. Grouping the Elements Groups 1 and 2: Very Reactive Metals Groups 1 and 2: Very Reactive Metals Elements whose atoms need to gain, lose, or share only one or 2 atoms are very reactive. Elements whose atoms need to gain, lose, or share only one or 2 atoms are very reactive. Elements in group 1 or 2 are only found in compounds in nature. Elements in group 1 or 2 are only found in compounds in nature.

7. Grouping the Elements Group 1: Alkali Metals Group 1: Alkali Metals Soft: cut with a knife! Soft: cut with a knife! Most reactive of metals Most reactive of metals Shiny, silver colored, low density Shiny, silver colored, low density React with WATER React with WATER To periodic table To periodic table To periodic table To periodic table

8. Grouping the Elements Group 2: Alkaline- Earth Metals Group 2: Alkaline- Earth Metals Not as reactive as alkali metals Not as reactive as alkali metals Harder to lose 2 electrons from valence shell Harder to lose 2 electrons from valence shell Calcium: important in nutrition Calcium: important in nutrition

9. Grouping the Elements Groups 3-12: Transition metals Groups 3-12: Transition metals Groups 13-16: Groups with Metalloids Groups 13-16: Groups with Metalloids

10. Grouping the Elements Group 17: The Halogens Group 17: The Halogens Very reactive nonmetals Very reactive nonmetals React easily, especially with metals React easily, especially with metals Some properties are quite different between the halogens Some properties are quite different between the halogens Chlorine is yellowish gas- disinfect water Chlorine is yellowish gas- disinfect water Iodine is dark red liquid- with alcohol to disinfect in hospitals Iodine is dark red liquid- with alcohol to disinfect in hospitals

11. Grouping the Elements Group 18: Noble gasses Group 18: Noble gasses UNREACTIVE nonmetals UNREACTIVE nonmetals All found in atmosphere in small amounts- argon is most plentiful- 1% of the atmosphere All found in atmosphere in small amounts- argon is most plentiful- 1% of the atmosphere Neon is unreactive, but it has it’s uses…

12. Grouping the Elements Hydrogen is in class of its own Hydrogen is in class of its own Like alkali metals, has one valence electron: REACTIVE Like alkali metals, has one valence electron: REACTIVE Physical properties more like nonmetals Physical properties more like nonmetals Most abundant element in universe! Most abundant element in universe!