Cornell Note — Overview of the Periodic Table (Pinned) — Notes

Periodic Table Overview Source: Wikimedia Commons — Modern Long-Form Periodic Table

Section	Content
Cue Column	Main Notes
What is Moseley's periodic law?	Physical and chemical properties of elements are periodic functions of their atomic numbers (not atomic masses). Proposed in 1913.
How many periods & groups?	7 periods (horizontal rows) + 18 groups (vertical columns)
What are the four blocks?	s-block (Groups 1–2), p-block (Groups 13–18), d-block (Groups 3–12), f-block (lanthanoids + actinoids)
Outer configuration of s-block?	$ns^1$ (Group 1) and $ns^2$ (Group 2)
Outer configuration of p-block?	$ns^2\,np^{1\text{–}6}$
Outer configuration of d-block?	$(n-1)d^{1\text{–}10}\,ns^{0\text{–}2}$
Outer configuration of f-block?	$(n-2)f^{1\text{–}14}$
Period number = ?	Highest principal quantum number (n) of valence electrons
Group number (s/p-block) = ?	Number of valence electrons (for s + p blocks in main groups)

Summary (in own words): The modern periodic table arranges 118 known elements by increasing atomic number into 7 periods and 18 groups. Each block (s, p, d, f) tells you which subshell the last electron enters. Period = the shell being filled; group = the valence electron count for main-group elements.