The Periodic Table and Periodic Law

How the real exam tests it

Questions from real CSCA papers that test this concept. Work each one out before you open the answer.

1. CSCA Chemistry December 2025 Past Paper
   Which group of elements belongs to the same main group? ( )
   • A. Hydrogen, lithium, sodium
   • B. Carbon, oxygen, sulfur
   • C. Hydrogen, carbon, nitrogen
   • D. Sodium, magnesium, aluminum
   Show answer & solution

   Answer: A

   Answer: A Lithium and sodium are in Group 1 (IA), and hydrogen is placed at the top of Group IA, so hydrogen, lithium and sodium belong to the same main group. The other sets span several groups.
   See it in the full CSCA Chemistry December 2025 Past Paper
2. CSCA Chemistry April 2026 Past Paper
   The position of sulfur (S) in the periodic table is ( ).
   • A. Period 2, Group VIA
   • B. Period 2, Group VIIA
   • C. Period 3, Group VIA
   • D. Period 3, Group VIIA
   Show answer & solution

   Answer: C

   Answer: C S is located in Period 3, Group VIA of the periodic table.
   Take the full CSCA Chemistry April 2026 Past Paper — timed & graded
3. CSCA Chemistry March 2026 Past Paper
   Element 34 selenium (Se) is located at
   • A．Period 3, Group VIA
   • B．Period 4, Group VIA
   • C．Period 4, Group VIIA
   • D．Period 3, Group VIIA
   Show answer & solution

   Answer: B

   Se(Z=34): $[ \operatorname { Ar } ] 3 d ^ { 10 } 4 s ^ { 2 } 4 p ^ { 4 } \rightarrow$ Period 4, Group VIA. Answer: B.
   Take the full CSCA Chemistry March 2026 Past Paper — timed & graded