The periodic law and the periodic table
Answers are for parents and teachers.
1
For the element with atomic number 16 give the period, group, higher oxide and hydrogen compound.
Period 3, main subgroup of group VI (sulfur); higher oxide SO₃, hydrogen compound H₂S.
2
Find the total number of elements in periods 6 and 7.
64
3
How many elements are there in periods 1 to 5 altogether?
54
4
Which is the more active metal, Mg or Ca, and why?
Ca: it is lower in the same group, has the larger atomic radius and gives up its outer electrons more easily.
5
How does the modern wording of the periodic law differ from Mendeleev’s?
Mendeleev tied the properties to atomic mass; today they are tied to the nuclear charge (atomic number).