By convention, the symbol Z is assigned to the number of protons in the nucleus, or simply, the atomic number of an element. This is actually used when you want to determine the effective nuclear charge of a specific electron of an element. The equation is:
Z* = Z - S
where
Z* is the effective nuclear charge
Z is the atomic number
S is the number of electrons between the electron in question and the nucleus
There is due to a phenomenon called the shielding effect. This effect states that the farther the electron is from the nucleus, the lesser is its pull of force to the nucleus. That is the reason why the valence electrons (outermost electrons) are the ones always involved in chemicals reactions. Because they are not that strongly bonded to the nucleus of an atom.
Answer:
2.30 × 10⁻⁶ M
Explanation:
Step 1: Given data
Concentration of Mg²⁺ ([Mg²⁺]): 0.039 M
Solubility product constant of Mg(OH)₂ (Ksp): 2.06 × 10⁻¹³
Step 2: Write the reaction for the solution of Mg(OH)₂
Mg(OH)₂(s) ⇄ Mg²⁺(aq) + 2 OH⁻(aq)
Step 3: Calculate the minimum [OH⁻] required to trigger the precipitation of Mg²⁺ as Mg(OH)₂
We will use the following expression.
Ksp = 2.06 × 10⁻¹³ = [Mg²⁺] × [OH⁻]²
[OH⁻] = 2.30 × 10⁻⁶ M
The hydroxide (OH) in the metallic hydroxide will react with the hydrogen in an acid to form H2O. The remaining ions will combine to form a salt. Therefore a metal hydroxide and an acid will form a salt + water.
The location where the mercury level of the barometer would be the lowest is at the very high altitudes of the Earth's atmosphere (about 100 km), since air pressure decreases as altitude increases.
