The significance of the periodic law
Answers are for parents and teachers.
1
Name the period, group and name of the element with configuration [Ar] 3d⁶ 4s².
Period 4, group VIII B, iron.
2
How many electrons does the Fe³⁺ ion have? (Z = 26)
23
3
Arrange Na, Mg, Al in order of increasing reducing power and explain why.
Al < Mg < Na: toward the left the atomic radius is larger and the electron leaves more easily.
4
Find the oxidation state of chlorine in HClO₄ and explain that it matches the group number.
+7; Cl is in group VII A, and the highest oxidation state equals the group number.
5
State the group of elements whose highest oxide is EO₂ and which form a hydrogen compound EH₄.
Group IV A (C, Si).