The periodic law
Answers are for parents and teachers.
1
Write the highest oxide of Mg and its relative molecular mass.
MgO, 40
2
Calculate the relative molecular mass of Cl₂O₇ (Aᵣ(Cl) = 35.5).
183
3
What is the highest oxide of aluminium? Does it form a volatile hydrogen compound?
Al₂O₃; as a metal it does not form a volatile hydrogen compound.
4
For the element with atomic number 16 write its symbol, highest oxide and hydrogen compound.
S, SO₃, H₂S
5
Why is Mendeleev’s system called “periodic”? Write briefly.
Properties repeat after a certain interval: each period (except the first) starts with an alkali metal and ends with a noble gas.