Periodic Table and Element Families

Discussion of Group 1 metals, referred to as alkali metals including lithium, sodium, potassium, rubidium, cesium, and francium.
Reactivity of Group 1 Metals:
- Highly reactive due to low ionization energies.
- Stored in kerosene or mineral oil to prevent reactions with oxygen and moisture in air.

Appearance: Dull gray due to oxide/nitride coating.
Physical Properties: Soft, can be cut with a knife.
Conductivity: Excellent conductor of electricity.
Reactivity with water: Floats, undergoes a single displacement reaction producing hydrogen gas and lithium hydroxide.
Indicator: Use of phenolphthalein turns pink in the presence of lithium hydroxide.

Stored similarly under mineral oil to limit oxygen reaction.
Appearance: Coated in oxide, much softer than lithium.
Reactivity: Rapid reaction with water resulting in hydrogen gas production.
Visualization: Metal moves across the surface due to hydrogen gas, exothermic reaction melts sodium, producing sodium hydroxide (indicated by phenolphthalein).

Stored under mineral oil, coated with gray oxide.
Extremely soft, can be easily flattened.
Very rapid reaction with water, more vigorous than sodium.
Products include potassium hydroxide; identified similarly using phenolphthalein.

As you move down the group:
- Reactivity increases.
- Softness increases.
- Ionization energy decreases.

Discussed properties of alkaline earth metals such as magnesium.
Reactivity: Increases across the period; higher ionization energy than group one.
- Magnesium (Mg):
- Appearance: Shiny surface, conducts electricity, sinks in water.
- Reactivity: Slow at room temperature with water; reaction speeds up when heated, eventually producing magnesium hydroxide and steam.
- Naming Convention: Known as alkaline earth metals, producing highly soluble hydroxides.

Going down the family, elements become more metallic and active.
Transition from low reactivity in magnesium (higher ionization energy than sodium) to more vigorous reactions in heavier alkaline earth metals.

Named inactive due to their low reactivity; termed "noble" since they don’t combine easily with other elements.
Uses of noble gases like argon in light bulbs to prevent oxidation of filaments.
Uses in flash photography, welding (for preventing oxidation), and safety in balloons (helium over hydrogen).

Elements known for forming salts; includes fluorine, chlorine, bromine, and iodine (with radioactive astatine).
Represent phases: gas (F2, Cl2), liquid (Br2), solid (I2).
- Unique in having all three states within one family.

Demonstrative properties of iodine showcasing sublimation (change from solid to gas).
Deposition when heated and subsequently cooled, leading to colored crystals being formed.

Segmentation in the periodic table by a jagged black line distinguishing metals and nonmetals, with metalloids located nearby.
Metalloid characteristics: electrical conductivity, luster, malleability versus brittleness; notable behaviors regarding conductivity.
Conductivity Behavior:
- Metals: Higher temperature increases resistance; thus, less conductivity.
- Nonmetals: Higher temperature decreases resistance; thus, better conductivity.

Found in the middle of the periodic table, they possess variable oxidation states, leading to complexity in prediction of their properties relative to other elements.
Colorful compounds enhance their visual appeal in experiments compared to more common elements.
- Noteworthy that transition metal ions often result in vivid colors depending on oxidation state.
Formation of Complex Ions (e.g., copperammonia complex).

Positioned below the main table; lanthanides often referred to as rare earth metals due to similar chemistries leading to co-occurrence.
- Notable use in creating strong magnets and other industrial applications.
Actinides: Radioactive elements with limited examples in nature (e.g., Uranium, Thorium).
- Majority are synthetic and carry hazardous implications.

Illustrated through predictions of chemical formulas based on family characteristics.
Limitations of the Table:
- Original atomic weight-based organization flawed; with noted exceptions.
- Hydrogen’s ambiguous classification across different groups.
- First family members’ deviation from trends noticed with subsequent members.

Upcoming lectures to explain the scientific reasons behind trends and behaviors of elements concerning atomic structure.
Reference toward structure of atoms will further elucidate periodic trends in chemistry.