Introduction to s and p Block Elements

Introduction to s and p Block Elements

• This session explores the properties, trends, and applications of s and p block elements.

Groups and Periods

• The periodic table is organized into groups (vertical columns) and periods (horizontal rows).
• Elements in the same group have similar chemical properties.
• Elements are arranged in order of increasing atomic number.

Group Classification

• The elements are categorized as s-block, p-block, d-block, and f-block, based on their electronic configuration.
• These categories are displayed on the periodic table, showing their corresponding classifications.

Valence Electron Configuration

• Valence electrons are the electrons in the outermost shell of an atom.
• The valence electron configuration determines the chemical properties of an element.
• s-block elements have ns1 or ns2 valence electron configuration.
• p-block elements have ns2 np1-6 valence electron configuration.

Electronegativity and Ionization Energy

• Electronegativity is an atom's tendency to attract electrons.
• Electronegativity increases across a period and decreases down a group.
• Ionization energy is the energy needed to remove an electron from an atom.
• Ionization energy increases across a period and decreases down a group.

Chemical Reactivity and Trends

• Reactivity in s and p block elements increases down a group, and across a period (for p block elements).
  • Valence electrons are easier to remove from further away elements.
• Reactivity in s block elements decreases across a period, in p-block it is more complex due to electronegativity and ionization energy.

Oxidation States

• Oxidation state is the hypothetical charge an atom would have if all bonds were ionic.
• Maximum oxidation state generally equals to the group number.
  • Oxygen is usually -2, but there are exceptions and are noted.

Important Notes

• Halogens in the p-block have a maximum oxidation state of +7 (except fluorine, which has a lower value).
• P-block elements demonstrate variable oxidation states when bound to N, S, or Cl.

Metals

• All metals are solids except mercury, which is liquid.
• Metals are lustrous, and good conductors of heat and electricity.
• Metals can be hammered or shaped (malleable), and drawn into wires (ductile).
• Metallic oxides are basic, like Na₂O.
• Metallic halides, oxides, and hydrides are generally ionic compounds.
• Electronegativity of metals ranges between 0.7 and 1.8, and they form positive ions like Na+, Mg²+, and Al³+.

Non-Metals

• Non-metals vary in their physical states (solid, liquid, or gas).
• Non-metals are poor conductors of heat and electricity.
• Non-metals are neither malleable nor ductile.
• Non-metallic oxides are acidic (e.g., SO₂).
• Non-metallic halides, oxides, and hydrides are often covalent compounds.
• Electronegativities for nonmetals are between ~2.2 - ~4.0

Semi-metals (Metalloids)

• Semi-metals are intermediate in their properties between metals and non-metals.
• Semi-metals are often semiconductors, with intermediate electrical and thermal conductivity.
• Semi-metals are brittle.
• Semi-metal oxides are usually amphoteric.

Practical Applications of s and p-Block Elements

• s and p block elements are crucial in electronics, with silicon used in semiconductors and lithium in batteries.
• Halogens are used in disinfectants and medications.
• Calcium is used in manufacturing cement and concrete.
• Phosphorus is a key plant nutrient and is used in fertilizer.