Answer:
Mg₁₂ = 1s² 2s² 2p⁶ 3s²
Explanation:
Abbreviated and unabbreviated electronic configuration:
The abbreviated electronic configuration uses the noble gas configuration i.e complete electronic shells. For example, the atomic number of neon is ten and magnesium is twelve. The abbreviated electronic configuration of magnesium is written by using the neon abbreviation in following way:
The electronic configuration of neon is given below:
Ne₁₀ = 1s² 2s² 2p⁶
The abbreviated electronic configuration of magnesium:
Mg₁₂ = [Ne] 3s²
While the unabbreviated electronic configuration is written without using noble gas electronic configuration.
Unabbreviated electronic configuration of magnesium:
Mg₁₂ = 1s² 2s² 2p⁶ 3s²
By adding the enthalpies of the intermediate reactions together to get the enthalpy of the desired reaction
The reaction is not balanced
<h3>Further explanation</h3>
Given
Reaction
2Fe(s)+3O₂(g)⇒2Fe₂O₃(s)
Required
The number of atoms
Solution
In a balanced chemical equation, the number of atoms in the compound that reacts (the reactants and products) will have the same number
Reactants : Fe(s)+O₂(g)
Fe = 2 atoms
O = 3 x 2 = 6 atoms
Products : Fe₂O₃(s)
Fe = 2 x 2 = 4 atoms
O = 2 x 3 = 6 atoms
The reaction is not balanced because the number of Fe atoms is not the same
The balanced reaction should be:
4Fe(s)+3O₂(g)⇒2Fe₂O₃(s)
Remembering that
d = m ÷ v
d = ?
m = 89 g
v = 10 cm³
Therefore:
d = 89 ÷ 10
d = 8,9 g÷cm³
