2.2 Navigating the Periodic Table of Elements:

  • Periodic table:

    • 18 columns

    • 7 rows

GROUPS AND PERIODS:

  • Group/Family of Elements:

    • elements that appear in the same column in the periodic table

    • Groups: identified by group # at the top

    • Main group of elements:

      • include groups 1A-1B, and last 6 columns = 3A-8A

      • Group 1A: alkali metals

      • Group 2A: alkaline earth metals

      • Group 7A: halogens

      • Group 8A: noble gases

    • Transition elements:

      • in the middle of the periodic table

      • groups 1B-8B

    • Inner Transition elements:

      • 2 rows of 14 elements each

      • below the main body of table

      • many of these elements are radioactive.

  • Elements within a group exhibit similar physical and chemical properties

  • Row of Elements: also known as a period

  • 1st row:

    • has only 2 elements: hydrogen and helium

The periodic table highlight of groups:

  • Alkali Metals

  • Alkaline Earth Metals

    • they react with oxygen to produce metal oxides when heated.

  • Halogens

  • Noble gases

  • Transition metals

  • Inner Transition Elements

METALS, NONMETALS, AND METALLOIDS:

  • elements can be classified into:

    • metals:

      • will show up to the left

    • nonmetals:

      • right diagonally

    • metalloids:

      • boron

      • silicon

      • germanium

      • arsenic

      • antimony

      • tellurium

      • polonium

      • astatine

      • these have properties of both metals and nonmetals.

Physical properties of metals and nonmetals

  • metals:

    • shiny

    • exist as solids at room temp

    • good conductors of electricity

    • flexible

  • nonmetals:

    • dull

    • exist as solids, liquids, and gases at room temp

    • poor conductors of electricity

    • brittle, hard, or soft

IMPORTANT ELEMENTS IN BIOCHEMISTRY AND MEDICINE:

  • 6 building block elements found in living organisms:

    • carbon

    • hydrogen

    • nitrogen

    • oxygen

    • phosphorus

    • sulfur

  • 7 macronutrients:

    • elements that need to be supplied through the diet

    • 100 mg/day

    • sodium

    • potassium

    • magnesium

    • calcium

    • phosphorus

    • sulfur

    • chlorine

  • micronutrients: 12 elements needed daily