Chemical Formulae

Question 1

All elements (except Noble Gases) can form ions. What is an ion?

Answer 1

Ions are charged atoms. In an ion, the number of electrons is not equal to the number of protons. During chemical reactions, electrons transfer from one atom to another atom, forming a bond.

Question 2

What ions are positively charged and what ions are negatively charged?

Answer 2

Cations are positively charged and anions are negatively charged.

Question 3

Here is an example of writing chemical formulae.
1. Mg + Cl
= Mg+2 + Cl-1
= Mg-1 + Cl+2
= MgCl2

Now, write these chemical formulae.
1. Ba + Cl
2. Iron (III) Oxide
3. Zinc (II) Bromide
4. Hydrogen Sulfide
5. Sodium Hydroxide
6. Ammonium Sulfate
7. Beryllium Phosphate

Answer 3

1. BaCl2
2. Fe203
3. ZnBr2
4. H2S
5. Na0H
6. (NH4)2S04
7. Be3(P04)2

Question 4

Rules to remember:
HCl - Hydrochloric Acid
H2S04 - Sulfuric Acid
HN03 - Nitric Acid
CH3C00H - Ethanoic Acid
S04 - Sulfate
S03 - Sulfite
P04 - Phosphate
Mn04 - Permanganate
S04 = -2
P04 = -3
C03 = -2