The picture of Au₃N is attached below.
The first part of the picture shows the formation of Au and N ions.
Formation of Au⁺¹ :
As Gold has one valence electron in 6s¹ therefore, it will loose it to form Au⁺¹. In case of Au₃N three atoms of Au looses three electrons to form three Au⁺¹ ions.
Formation of N⁻³ :
As Nitrogen has 5 valence elctrions therefore, it will gain three electrons that lost by Au to form Nitrite (i.e. N⁻³)
Formation of Au₃N:
Three cations of Au⁺ combines with one anion of N⁻³ to form a neutral ionic compound i.e. Au₃N as shown in second part of the picture.
C. The temperature decreases because the most energetic molecules escape.
Minerals determines the composition of a rock
<h3>a) <u>Answer;</u></h3>
A- 7.30 M
<h3><u>Explanation;</u></h3>
3.65 Sodium sulfate
Na2(SO4) dissociates to give sodium ions and sulfate ions.
Na2(SO4) → 2Na+ + SO₄²₋
Therefore, twice the concentration of sodium ions as far as molarity is concerned.
<em><u>Concentration of sodium ions = 3.65 × 2= 7.3 M</u></em>
<h3>b) <u> Answer;</u></h3>
B- 2.76 M
<h3><u>Explanation;</u></h3>
b) 1.38 M sodium carbonate
Sodium carbonate dissociates completely to yield Sodium ions and carbonate ions
Na₂CO₃ → 2Na+ + CO₃²₋
The concentration of sodium ions will be twice the concentration of initial compound since it has a ratio of two.
<em>Concentration of sodium ions = 1.38 ×2 </em>
<em> = 2.76 M</em>
<h3>
c) <u>
Answer;</u></h3>
<em>0.785 M</em>
<h3><u>
Explanation;</u></h3>
b) 0.785 sodium bicarbonate
Sodium bicarbonate dissociates completely to sodium ions and a bicarbonate ions.
NaHCO₃ →Na+ + HCO₃⁻
In this case the concentration of Na+ will be equal to the concentration of the original compound since they share the same ratio.
Thus; <em><u>Na+ concentration = 0.785 M</u></em>
Thus, one atom of carbon will combine with two atoms of oxygen to form the molecule CO 2 ( carbon dioxide ). (b) From the chemical formula of the compound aluminium oxide Al 2 O 3 , the valency of aluminium can be determined. ... Hence the valency of aluminium is 3