So we have a question for chem. homework and i really don't understand. can you please explain it.....
Question:There is a change in the type of oxides formed with the period three elements. Indicate the type of compounds formed (ionic, amphoteric, covalent) when the period three elements react with oxygen. Give balanced equations.
Period three elements are Na, Mg, Al, Si, P, S, and Cl (not including Ar).
Na + O2 ==> Na2O You balance.
Mg + O2 ==> MgO Both Na2O and MgO are basic oxides.
Al + O2 ==> Al2O3 an amphotere.
S + O2 ==> SO2 an acidic oxide.
I think the point of this exercise is to make you aware that the oxides go from basic on the left (adding water makes NaOH or Mg(OH)2 but Mg(OH)2 is less basic (more acidic) than NaOH), to Al which is an amphotere (sometimes acidic, sometimes basic) to P, S, and Cl that become more acidic, again, from left to right. You must balance all of the equations.
To answer this question, we need to understand the periodic trend and the types of oxides formed by period three elements.
1. First, let's review the periodic trend for period three elements as we move across the period from left to right. The elements in period three include sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), chlorine (Cl), and argon (Ar). As we move across the period, the atomic radius decreases while the electronegativity increases.
2. Next, let's consider the different types of oxides that can be formed when these elements react with oxygen. There are three types of oxides: ionic, covalent, and amphoteric.
- Ionic oxides: Ionic oxides are formed when the metal elements react with oxygen. These oxides consist of metal cations (positive ions) and oxide anions (O2-). Since most of the metals in period three are located on the left-hand side of the periodic table, they tend to form ionic oxides.
- Covalent oxides: Covalent oxides are formed when nonmetal elements react with oxygen. These oxides consist of molecules held together by covalent bonds. Since most of the nonmetals in period three are located on the right-hand side of the periodic table, they tend to form covalent oxides.
- Amphoteric oxides: Amphoteric oxides are oxides that can exhibit both acidic and basic properties, meaning they can react with both acids and bases. Aluminum (Al) is an example of a period three element that can form an amphoteric oxide.
3. Now, let's provide balanced equations for the reaction of each period three element with oxygen:
a) Sodium (Na): Sodium is a metal, so it forms an ionic oxide.
Balanced equation: 4Na + O2 -> 2Na2O
b) Magnesium (Mg): Magnesium is a metal, so it forms an ionic oxide.
Balanced equation: 2Mg + O2 -> 2MgO
c) Aluminum (Al): Aluminum is an amphoteric element, so it forms an amphoteric oxide.
Balanced equation: 4Al + 3O2 -> 2Al2O3
d) Silicon (Si): Silicon is a nonmetal, so it forms a covalent oxide.
Balanced equation: Si + O2 -> SiO2
e) Phosphorus (P): Phosphorus is a nonmetal, so it forms a covalent oxide.
Balanced equation: 4P + 5O2 -> 2P2O5
f) Sulfur (S): Sulfur is a nonmetal, so it forms a covalent oxide.
Balanced equation: 2S + 3O2 -> 2SO3
g) Chlorine (Cl): Chlorine is a nonmetal, so it forms a covalent oxide.
Balanced equation: Cl2 + O2 -> Cl2O
h) Argon (Ar): Argon is an inert gas and does not readily react with oxygen, so it does not form an oxide.
I hope this explanation helps you understand the concept of the type of oxides formed by period three elements when they react with oxygen!