Overview
This lecture covers the IUPAC nomenclature for elements with atomic numbers above 100, classification and prediction of block, group, and period for elements, and key features of s, p, d, and f block elements, along with important NCERT highlights.
IUPAC Nomenclature for Elements (Z > 100)
- Elements with atomic number over 100 are named using root words for each digit, followed by "ium."
- Digit roots: 0 = nil (n), 1 = un (u), 2 = bi (b), 3 = tri (t), 4 = quad (q), 5 = pent (p), 6 = hex (h), 7 = sept (s), 8 = oct (o), 9 = enn (e).
- Example: Element 101 = un-nil-un-ium = Unnilunium (symbol: Uun).
- Symbols use the first letter from each root.
Classification & Prediction of Elements
- Period: Determined by the principal quantum number (n) of the outermost shell.
- Example: Nitrogen (Z=7) has configuration 1s²2s²2p³; period is 2.
- Block: Identified by the subshell into which the last electron enters (s, p, d, or f).
- Group (s-block): Equal to number of valence electrons.
- Group (p-block): Valence electrons + 10.
- Group (d-block): Total (n)s electrons + (n−1)d electrons.
S, P, D, and F Block Elements
S-block
- Groups 1 and 2; general configuration: ns¹ or ns².
- Form +1 (group 1) or +2 (group 2) ions.
- Metallic character increases down the group; high melting/boiling points (except for some exceptions).
- Soft, large size; left of periodic table.
P-block
- Groups 13–18; outer electrons in p subshell.
- Increased nonmetallic character left to right across period.
- Contains metals, non-metals, and metalloids.
- Metallic character increases down the group.
D-block (Transition Elements)
- Last electron enters d subshell; located in middle of periodic table.
- Generally form colored compounds; exceptions in group 12.
F-block (Inner Transition Elements)
- Last electron enters f subshell (n–2).
- Includes lanthanoids (58–71) and actinoids (90–103).
Properties of Metals, Non-metals, and Metalloids (as per NCERT)
- Metals: 78% of elements; mostly solids; high melting/boiling point; malleable, ductile, good conductors.
- Non-metals: Top right of periodic table; solids or gases at room temp; low melting/boiling point (except boron, carbon); poor conductors; brittle.
- Metalloids: Lie along zigzag line; have properties of both metals and non-metals.
Key Terms & Definitions
- IUPAC nomenclature — Systematic naming for new elements using digit roots and "ium."
- Valence electrons — Electrons in the outermost shell.
- Block — Category based on subshell (s, p, d, f) of last entering electron.
- Metalloids — Elements with both metallic and non-metallic properties, found diagonally in p-block.
Action Items / Next Steps
- Complete homework: predict period, block, group for given atomic numbers (29, 13, Fe, Sc).
- Answer NCERT in-text and back questions given in lecture (e.g., element 117, 120, 14, 55).
- Create mnemonic tricks for lanthanoid and actinoid series.
- Revise electronic configurations and practice classifying elements.