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

1

What is the second period in the periodic table?

Li, Be, B, C, N, O, F, Ne

Be, Mg, Ca, Sr, Ba, Ra

Na, Mg, Al, Si, P, S, Cl, Ar

F, Cl, Br, I, At

2

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

O

Ne

Mn

Ca

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?

Halogens are colorful and corrosive nonmetals and are diatomic molecules in nature

Noble gases are the last group of the periodic table and are inert gases

Alkali metals form the first group of the periodic table while alkaline-earth metals form the second

None of the above

5

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

6.0 x 1023 atoms

1.2 x 1024 atoms

2.4 x 1024 atoms

We need the mass to answer this question

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 ${\mathrm{N}}_{{\mathrm{H}}_{2}}$

6

What is the SI unit of molar mass?

g

g.mol-1

mol

no unit

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

7

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

1.30 x 10-2 mol

0.130

0.207

1.18 x 103 mol

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