# Quiz - The Periodic Table and Atoms | The Periodic Table and Atoms

1

What is the second period in the periodic table?

2

Which of the following is not an element of the main group?

Main groups: the 2 groups at the extreme left and the 6 groups at the extreme right of the periodic table. Manganese (Mn) is in group 7 ⇒ it is a transition metal

3

Which of the following statements is incorrect?

4

How many atoms of hydrogen do you have in 2.0 moles of H2?

n = $\frac{\mathrm{N}}{{\mathrm{N}}_{\mathrm{A}}}$   ⇒   number of dihydrogen atoms ${\mathrm{N}}_{{\mathrm{H}}_{2}}$ = ${\mathrm{n}}_{{\mathrm{H}}_{2}}$ x NA = 2.0 x 6.022 x 1023 atoms

⇒ number of hydrogen atoms ${\mathrm{N}}_{\mathrm{H}}$ = 2 x ${\mathrm{N}}_{{\mathrm{H}}_{2}}$

5

What is the SI unit of molar mass?

The SI unit of molar mass M is g.mol-1

6

What is the mole number of 12.4 g of MgCl2 (MMg = 24.3 g.mol-1, MCl = 35.5 g.mol-1)?

mole number ${\mathrm{n}}_{{\mathrm{MgCl}}_{2}}$ = $\frac{{\mathrm{m}}_{{\mathrm{MgCl}}_{2}}}{{\mathrm{M}}_{{\mathrm{MgCl}}_{2}}}$

with MMgCl2 = MMg + 2 x MCl = 95.3 g.mol-1