# Quiz | Atoms and Molecules

1

What is the chemical symbol of magnesium?

M

Ma

Na

Mg

The symbol of Magnesium in the periodic table is Mg

2

The sublimation is the transition of a substance...

from the gas to the solid state

from the solid to the gas state

from the liquid to the solid state

from the solid to the liquid state

3

Which of the following statements about chemical reaction is incorrect?

New atoms are created

Atoms can be rearranged

Atoms of molecules can be separated

Atoms are recombined to form new compounds

In a chemical reaction, atoms are rearranged, separated, or recombined to form new compounds but are not created or destroyed

4

Which of the following statements is correct?

Neutrons are located in the nucleus and have the same mass and charge than protons

An atom is mostly made up of empty spaces

The mass of an atom is evenly distributed throughout its volume

All of the above

Most of the mass of an atom is concentrated in its tiny nucleus

5

How many protons, electrons and neutrons does 40Ca2+ have (knowing that calcium is the twentieth element in the periodic table)?

20 protons, 20 neutrons, 18 electrons

20 protons, 20 neutrons, 22 electrons

20 protons, 40 neutrons, 18 electrons

22 protons, 20 neutrons, 20 electrons

Calcium is the 20th element in the periodic table ⇒ 20 protons
mass number = protons + neutrons = 40 ⇒ 20 neutrons
charge = protons – electrons = +2 ⇒ 18 electrons

6

What is the nuclear symbol for an atom with the following subatomic particles: 8 protons, 8 neutrons, 10 electrons?

${}_{8}{}^{16}\mathrm{O}_{2}$

${}_{8}{}^{16}\mathrm{O}^{10}$

${}_{8}{}^{16}\mathrm{O}^{2-}$

${}_{8}{}^{16}\mathrm{0}^{2+}$

Z = atomic number = number of protons ⇒ Z = 8
A = mass number = protons + neutrons ⇒ A = 16
Q = charge = protons – electrons ⇒ Q = - 2

7

How do you name the acid HBr?

Hydrogen bromide

Monohydrogen bromide

Bromic acid

Hydrobromic acid

Binary Acid Naming: hydro- + first syllable of the anion + suffix -ic + acid