Learn & Review: Periodic Table of Elements: Metals, Nonmetals, Valence Electrons, Charges

Summary of Periodic Table and Element Properties

This video provides an overview of the Periodic Table, focusing on the properties of elements within different groups and their general characteristics. It also explains fundamental atomic structure and how to determine the number of protons, neutrons, and electrons.

I. Periodic Table Groups and Properties

The Periodic Table is organized into groups (columns) and periods (rows), with elements sharing similar properties within the same group.

• Group 1A (Alkali Metals):

  • Includes Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium.
  • Hydrogen is in this group but is a nonmetal; the rest are alkali metals.
  • Properties: Highly reactive metals, react explosively with water.
  • Valence Electrons: 1
  • Ion Formation: Tend to lose one electron to form +1 cations.
  • Reactivity: Most reactive metals. Francium is one of the most electropositive metals.

• Group 2A (Alkaline Earth Metals):

  • Includes Beryllium, Magnesium, Calcium, Strontium, and Barium.
  • Properties: Reactive metals, but less so than alkali metals.
  • Valence Electrons: 2
  • Ion Formation: Tend to lose two electrons to form +2 cations.
  • Magnesium is an example of an alkaline earth metal.

• Transition Metals:

  • Located in the middle block of the periodic table.
  • Examples: Zinc, Copper, Iron (Fe), Silver (Ag), Gold (Au), Platinum (Pt), Mercury (Hg).
  • Properties: Reactivity varies; some are reactive, others are not.
  • Cobalt is a transition metal.

• Inner Transition Metals:

  • Includes the Lanthanides (first row) and Actinides (second row).
  • Uranium is an example of an inner transition metal, part of the Actinide Series.
  • Many elements in this series, especially those with high atomic numbers (around 90 and above), are radioactive.

• Group 7A / 17 (Halogens):

  • Includes Fluorine, Chlorine, Bromine, and Iodine.
  • Properties: Highly reactive nonmetals, the most reactive nonmetals.
  • Valence Electrons: 7
  • Ion Formation: Tend to gain one electron to form -1 anions.
  • Bromine is a halogen.
  • Fluorine is the most electronegative element.

• Group 6A / 16 (Chalcogens):

  • Includes Oxygen, Sulfur, Selenium.
  • Properties: Nonmetals.
  • Valence Electrons: 6
  • Ion Formation: Tend to gain two electrons to form -2 anions.
  • Selenium is a chalcogen.

• Group 5A / 15:

  • Includes Nitrogen, Phosphorus, Arsenic.
  • Valence Electrons: 5
  • Ion Formation: Typically form -3 anions.

• Group 4A / 14:

  • Includes Carbon, Silicon, Germanium, Tin, Lead.
  • Valence Electrons: 4
  • Ion/Charge Formation: Can form +4 or +2 charges (e.g., Tin and Lead). Carbon and Silicon are less commonly seen in ionic forms.
  • Silicon and Germanium are common metalloids.

• Group 3A / 13:

  • Includes Boron, Aluminum, Gallium.
  • Valence Electrons: 3
  • Ion Formation: Form +3 cations.
  • Gallium is an example.

• Group 8A / 18 (Noble Gases):

  • Includes Helium, Neon, Argon, Krypton, Xenon, Radon.
  • Properties: Chemically inert (very stable, do not react easily).
  • Helium has 2 valence electrons (as it's in the first period).
  • Neon and others have 8 valence electrons.
  • Argon is a noble gas.

II. General Element Classifications

• Metals:

  • Located on the far left of the periodic table.
  • Properties: Conduct heat and electricity, malleable (can be hammered into sheets), ductile (can be pulled into wires).
  • Electron Behavior: Like to give away electrons; electropositive.
  • Form positive ions (cations).
  • Most metals are solid at room temperature, with Mercury being a notable exception (liquid).
  • Potassium, Magnesium, Cobalt, and Uranium are classified as metals. Manganese is a metal that conducts electricity. Nickel is a transition metal that gives away electrons.

• Nonmetals:

  • Located on the upper right side of the periodic table.
  • Properties: Do not conduct electricity (insulators).
  • Electron Behavior: Like to acquire electrons; electronegative.
  • Form negative ions (anions).
  • Most are gases or solids at room temperature, with Bromine being a liquid and Iodine a solid.
  • Bromine and Selenium are nonmetals.
  • Diatomic Elements: Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, Iodine exist as diatomic molecules (H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂).

• Metalloids:

  • Elements along a "stair-step" line on the periodic table, between metals and nonmetals.
  • Properties: Exhibit properties of both metals and nonmetals; conductivity is between metals and nonmetals.
  • Conduct a small amount of electricity, which increases with light or temperature.
  • Common examples: Silicon, Germanium.
  • Germanium is classified as a metalloid.

III. Atomic Structure and Properties

• Atomic Number:

  • The smaller number associated with an element on the periodic table.
  • Represents the number of protons in an atom's nucleus.
  • Determines the element's identity.
  • For a neutral atom, the atomic number also equals the number of electrons.

• Atomic Mass (Mass Number):

  • The larger number associated with an element.
  • Represents the total number of protons and neutrons in the nucleus.
  • Number of Neutrons = Atomic Mass - Atomic Number.

• Valence Electrons:

  • Electrons in the outermost energy level of an atom.
  • Determine an element's chemical reactivity and bonding behavior.
  • Lithium has 1 valence electron. Calcium has 2 valence electrons. Sulfur has 6 valence electrons. Chlorine has 7 valence electrons.

• Ions:

  • Atoms that have gained or lost electrons, resulting in a net electrical charge.
  • Cations: Positively charged ions (formed by losing electrons).
  • Anions: Negatively charged ions (formed by gaining electrons).
  • Number of Electrons in an Ion = Atomic Number - Charge.
  • Aluminum ion (Al³⁺) has 13 protons and 10 electrons.

• Forces within the Atom:

  • Electric Force: Causes repulsion between like charges (protons) and attraction between opposite charges (protons and electrons).
  • Strong Nuclear Force: A powerful force that overcomes the electric repulsion between protons, keeping the nucleus intact.
  • Electrons are attracted to the nucleus and stay in orbit due to this attraction and their high speed.

IV. Element Identification and Properties Quiz Examples

• Conductivity: Manganese (metal) conducts electricity; Phosphorus, Selenium, Chlorine, Krypton (nonmetals) do not. Graphite (an allotrope of Carbon) is an exception among nonmetals that conducts electricity.
• Valence Electrons: Potassium (Group 1) has 1; Calcium (Group 2) has 2; Gallium (Group 13) has 3; Chlorine (Group 17) has 7; Sulfur (Group 16) has 6. Calcium has two valence electrons.
• Forming Negative Ions (Anions): Nonmetals are most likely to form anions. Sulfur (Group 16) forms a -2 charge.
• Metals vs. Nonmetals vs. Metalloids:
  • Metals: Potassium, Magnesium, Cobalt, Uranium.
  • Nonmetals: Bromine, Selenium.
  • Metalloid: Germanium.
• Specific Group Identification:
  • Alkali Metal: Potassium.
  • Alkaline Earth Metal: Magnesium.
  • Transition Metal: Cobalt.
  • Inner Transition Metal: Uranium.
  • Halogen: Bromine.
  • Chalcogen: Selenium.
• Reactivity:
  • Most Reactive Metal: Potassium (Alkali Metal).
  • Most Reactive Nonmetal: Bromine (Halogen).
• Radioactivity: Uranium (heavy inner transition metal) is likely radioactive.
• Chemical Inertness: Argon (Noble Gas) is chemically inert.
• Electron Donation: Metals like Nickel (transition metal) want to give away electrons.
• Physical States at Room Temperature:
  • Diatomic Elements: H₂, N₂, O₂, F₂, Cl₂ (gases); Br₂ (liquid); I₂ (solid).
  • Metals: Mostly solid, Mercury (liquid).
  • Gallium: Solid at 25°C, melts around 30°C.